My group and I are meeting about every two weeks now for three hours, which is great for us as we all have hectic schedules. Tonight they fought the BBEG and her minions to end the first chapter of an old AP we're running (RotRL converted to 5e). Man, I was horrendous. I did my best to come up with descriptive dialogue during the fight. I did my best to tie the events of the session to their backstories. I watched a ton of my favorite DM's on Youtube to get inspired. And. . . the enjoyment level for the players was probably a 6 out of ten.
What ended up happening was a constant and slow beatdown of a sack of hit points and a fair amount of yawning. Here's where I think I need help:
1.) I REALLY want to bring a much stronger RP element to the game while they. . . don't. Ends up with my describing too much and in too much depth. However, a meta game that just involves number crunching is extremely boring to me and I want to have some fun, too.
2.) I thought I was prepared but continually forgot to track advantage, fear, use of spells, etc. This led to pretty decent pauses in the flow of combat occasionally.
3.) I allowed the combat to devolve into a bunch of people whacking each other while stationary until someone ran out of hit points.
4.) Because of an insane smite crit from the paladin, the BBEG never got off an actual attack. While she had a lot of hit points, she was constantly playing catch up. This led for a really anticlimactic encounter.
5.) I didn't end on a cliff-hanger so the session ended somewhat antimactically, as well.
I realize that I'm writing issues that seem directly solvable but the real issue here is that I think that I'm all ready to address these things prior to play and in prep, etc., and yet they keep somehow happening. Any help here would be wildly appreciated, thank you!
A few ideas:
Legendary Enemies, or anyone you want to be the setpeice of the battle, needs an extra reaction, and the ability to mitigate damage, and a regen value. Maybe a whole extra turn.
Use terrain dynamically. Have feature of the terrain that can be used as cover, moved around/over, used against the players unless they take control of them, etc.
Include hazards as part of such battles, if it makes sense.
Always give your BBEG a lieutenant, and/or some minions, as others have said. If possible, give the BBEG a way to summon/activate 1 or more hazards, obstacles, terrain features, or allies.
Example: my latest BBEG was able to animate statues, and raise platforms in her hall. When she needed space, she had a pushback Blast, and a successful save still pushed the saving creature back, but half as much, so no matter what she got space.
Then, she could animate a statue as a bonus action, and it immediately could Move half its speed.
Lastly, when the party had her on the ropes, she pushed back, and raise herself on a platform, and then made the floor stagger into different levels, creating obstacles the party had to overcome to get to her. Her minions and summoned creature harried the party while she healed, and basically created a new phase of the battle.
Steal monster abilities from other d20 games, and/or give them spells or spell like abilities with a recharge mechanic. Ie, every turn roll a d6, and on a 4+, the recharge ability recharges, and can be used again on that turn.
Animated minions should be resurectable if needed.
Simplify your monsters by making effects part of the basic math. Ie, when running a dryad, have all of her attacks assume Shillelagh, and her defenses assume Barkskin. Alternately, have those effects come online when the monster is at half HP, or loses 1/4 HP, etc.
Find some quick reference printable tables and such, index cards or quick reference sheets for conditions, etc. for the players. Get them tracking their own stuff. Print out monsters so you can mark down current HP, and whatever notes you need, right on the monster. Also for quick reference.
I like to copy and paste stats onto a word doc, clean up the format, make whatever adjustments I need to, simplify redundant stuff, and print 1-3 pages of critters. Minions and such I will only keep 1/4 or so of the statblock.
Other people like using an index card per monster.
Edit. Got interrupted.