Agree with [MENTION=336]D'karr[/MENTION] - lack of a controller just means that minions are more threatening and swarms are very dangerous. A well built controller typically throws around lots of conditions; without one, your monsters won't be as bogged down.
Let's discuss monsters and combat. For the most part, this is advice when dealing with your 3 PCs.
Monster Mix
Minions: A few are ok, but don't fill the encounter with them. Why? They will frustrate your rogue. He does lots of damage, which is irrelevant when a minion has 1 HP. But a few can give your guys pause, or at least let them waste a round mopping up. Minions make great flanking friends for skirmishers. (When you have your other two guys, feel free to use more.)
Skirmishers: These you'll likely use a lot. They are mobile. They can potentially do a lot of damage, but they're not very dangerous. Skirmishers make great fodder for fighters, because fighters pin them down and beat on their heads. Your rogue can likely take these guys down if he can get CA.
Brutes: These are a mixed bag. They have lots of HP, and are supposed to do a lot of damage (especially with the newer math). The problem is that their attack bonus is low, and they often have boring powers (particularly the MM1-2 brutes). Consider increasing attack bonus, and making them out to be dangerous, and your guys will converge and wail on them.
Artillery: Unless the cleric is a ranged cleric, it means you have no ranged guys. Which makes artillery monsters more interesting. Artillery packs a punch with their ranged powers, but are dead in melee - thus you can put them behind a defensive wall, put them at the top of some stairs/other areas that take effort to get to, so that the players are spending a round or two just getting to the glass cannon that's firing at them (an eladrin can teleport - letting the rogue get to the artillery will make him feel awesome if he figures it out). Even if your cleric has ranged powers, he likely can't lay down the serious hurt, thus it means that fighter/rogue needs to get to the artillery guy. Artillery paired with say, a soldier and some minions, could make a long but tense fight.
Controllers: You can put a controller in a situation similar to the artillery, but there's more variety here. Controllers do two things well: Debuffing with conditions, and moving PCs around. They don't do a lot of damage. Which means that what makes a controller shine is either the environment they are in (various terrain to push PCs into) or the enemies they're with (dazing PCs so that skirmishers can do Sneak Attack damage, etc etc).
Lurkers: These are my favorite types. They are weak, potentially do the most damage, have to ambush, and can potentially hide/run away. Most lurkers have an ability to remain hidden, so the best tactic is to wait a round or two before having them pounce on someone. Particularly someone who is either hanging in the back, or who is wounded - therefore everyone has to rush to the person's aid. This can change an encounter completely, or at least add some sudden tension. However, use lurkers every now and then, not every fight.
Soldiers: Only use one of these, ever. Soldiers are your most boring monster. They are hard to hit, but do little damage. The only purpose of a soldier is to take the heat off your other monsters. Never use a soldier above the party's level. (When you have your other two guys, you can use one more soldier).
Elites/Solos For a 3 man team, an Elite is just about a solo (avoid solos unless you have a 5 man team). Pair an elite with a bucket full of minions, or two lower level monsters. Expect your PCs to focus fire on the elite guy, so he may have 2-3 rounds to live. Keep the Elite's defenses kinda low (never, ever use an elite soldier - boring as hell).
Monster level: Using monsters below the party level will permit you to use more of them. For a 3 man team, that's good.
Combat
You'll often find combat comes in two types: either the PCs barely scrape by, or they blow through the encounter. Usually the latter is the case. Expect it - PCs are very durable, and they will find ways to beat your monster's teeth in. Dont' get discouraged. Players love slaying monsters/being badass. So what you want to do is give them enough of a challenge so they're not bored, give them enough of a threat so they maybe were worried for a round.
Beware of Grind. This is where it's clear that the PCs are going to win, but there's a monster or two still alive. This is the point where the fight gets boring/tedious. What you want to do here is either: 1) Have the monster try to flee (PCs will usually chase those suckers down as hard as they can), 2) Have the monster surrender, or 3) Handwave the battle, because it's clear who's going to win.
Let's discuss monsters and combat. For the most part, this is advice when dealing with your 3 PCs.
Monster Mix
Minions: A few are ok, but don't fill the encounter with them. Why? They will frustrate your rogue. He does lots of damage, which is irrelevant when a minion has 1 HP. But a few can give your guys pause, or at least let them waste a round mopping up. Minions make great flanking friends for skirmishers. (When you have your other two guys, feel free to use more.)
Skirmishers: These you'll likely use a lot. They are mobile. They can potentially do a lot of damage, but they're not very dangerous. Skirmishers make great fodder for fighters, because fighters pin them down and beat on their heads. Your rogue can likely take these guys down if he can get CA.
Brutes: These are a mixed bag. They have lots of HP, and are supposed to do a lot of damage (especially with the newer math). The problem is that their attack bonus is low, and they often have boring powers (particularly the MM1-2 brutes). Consider increasing attack bonus, and making them out to be dangerous, and your guys will converge and wail on them.
Artillery: Unless the cleric is a ranged cleric, it means you have no ranged guys. Which makes artillery monsters more interesting. Artillery packs a punch with their ranged powers, but are dead in melee - thus you can put them behind a defensive wall, put them at the top of some stairs/other areas that take effort to get to, so that the players are spending a round or two just getting to the glass cannon that's firing at them (an eladrin can teleport - letting the rogue get to the artillery will make him feel awesome if he figures it out). Even if your cleric has ranged powers, he likely can't lay down the serious hurt, thus it means that fighter/rogue needs to get to the artillery guy. Artillery paired with say, a soldier and some minions, could make a long but tense fight.
Controllers: You can put a controller in a situation similar to the artillery, but there's more variety here. Controllers do two things well: Debuffing with conditions, and moving PCs around. They don't do a lot of damage. Which means that what makes a controller shine is either the environment they are in (various terrain to push PCs into) or the enemies they're with (dazing PCs so that skirmishers can do Sneak Attack damage, etc etc).
Lurkers: These are my favorite types. They are weak, potentially do the most damage, have to ambush, and can potentially hide/run away. Most lurkers have an ability to remain hidden, so the best tactic is to wait a round or two before having them pounce on someone. Particularly someone who is either hanging in the back, or who is wounded - therefore everyone has to rush to the person's aid. This can change an encounter completely, or at least add some sudden tension. However, use lurkers every now and then, not every fight.
Soldiers: Only use one of these, ever. Soldiers are your most boring monster. They are hard to hit, but do little damage. The only purpose of a soldier is to take the heat off your other monsters. Never use a soldier above the party's level. (When you have your other two guys, you can use one more soldier).
Elites/Solos For a 3 man team, an Elite is just about a solo (avoid solos unless you have a 5 man team). Pair an elite with a bucket full of minions, or two lower level monsters. Expect your PCs to focus fire on the elite guy, so he may have 2-3 rounds to live. Keep the Elite's defenses kinda low (never, ever use an elite soldier - boring as hell).
Monster level: Using monsters below the party level will permit you to use more of them. For a 3 man team, that's good.
Combat
You'll often find combat comes in two types: either the PCs barely scrape by, or they blow through the encounter. Usually the latter is the case. Expect it - PCs are very durable, and they will find ways to beat your monster's teeth in. Dont' get discouraged. Players love slaying monsters/being badass. So what you want to do is give them enough of a challenge so they're not bored, give them enough of a threat so they maybe were worried for a round.
Beware of Grind. This is where it's clear that the PCs are going to win, but there's a monster or two still alive. This is the point where the fight gets boring/tedious. What you want to do here is either: 1) Have the monster try to flee (PCs will usually chase those suckers down as hard as they can), 2) Have the monster surrender, or 3) Handwave the battle, because it's clear who's going to win.
