There are several ways to do this. Allowing all casters to have Eschew Materials as a bonus feat is a common house rule, as it allowing Sorcerers to use Meta-magic feats without spending a full round preparing to use it.
Another common house rule - at least around where I live - is that spells, once learned, are not forgotten. That is to say, if the spell book is lost, another can be created without bankrupting the wizard (or even the party). In effect, the wizard knows the spell well enough to rewrite it, but not quite well enough to cast it without first working it out in full again (by writing - or carving, see below - the spell out again). So the costs for writing in a spell already learned is only 1/10th the normal cost, although scribing a spell just learned is the normal price (which, as house ruled around here, is about half what the core rules suggest - in part because the cost of scribing spell is counted towards the character's suggested wealth per level, and having many spells quickly dries up that reserve otherwise.)
One I've played with a few times is using Spell staves instead of Spell books. Spells are carved into the staff, and each holds as many spells as the typical spell book (ie: 1 rune per spell level for each spell, each staff holding ~100 runes). The staffs can be brandished as a replacement for the somantic component, and each staff (to prevent easy breakage) gains a bonus to hardness and hit points equal to the level of the wizard wielding it (or the highest spell carved into it). It can be used as a weapon, but it works as if a typical quarterstaff. Spell sticks are smaller staffs - about the size of a wand and only able to hold about 25 runes.
Another (less common) house rule is to allow those researching a spell to draw from any accepted source (arcane, divine, WotC, third party, etc). Hmm, oh, I've seen it ruled that the monetary component of a spell (such as a 5k gp diamond or 25gp silver dust) can be replaced with xp on a 5 to 1 ratio (so it would be 1000 xp or 5 xp in the above examples). The reverse is also true: a spell that has a 100 xp cost could instead have a 500 gp material component used instead.
What else . . . .
Sorcerers get a feat every five levels - as with wizards, but unlike wizards, they are limited to heritage feats and meta-magic feats (not item creation feats).
I've seen various ways of altering familiars so that they are more like animal companions or other forms of enhancement, thus increasing their survivability a bit, but this tends to differ a bit each time I see it - each DM having his own style, and often altering that style from campaign to campaign as they seek to better balance their setup for this.
Most DMs adjust spell levels as they see fit for their settings. Some spells are raised a level or two, others (rarely) are lowered a level or two. Sometimes a spell is removed altogether. Sometimes the removal is permanent - no one can learn it. Sometimes it is not - the spell can either be researched or found, but it cannot be taken for free when a level is gained. Spells of the teleport, raise dead, scrying, true seeing, and so forth, along with many of the buffing spells, tend to often be raised a level or two or removed.
Sometimes the cost of creating permanent magic items (weapons, armor, wondrous items, and rings, usually) is increased - even doubled, or the level required for the feat is raised a few levels.
A less common houserule is to rule that magic is slightly chancy. Each time a spell is cast or a magic item is used a roll is made. If it rolls low (a 1 on d20, or perhaps a 1 on d10) then something odd happens - it fails, it has an opposite effect, it affects the caster or some random nearby target or area, a similar effect / spell (of equivalent level and same school of magic) occurs instead, a random metamagic or antimetamagic feat (or equivalent) is applied, something akin to psionic affects occur (such as a glow, sound, echoplasm, etc briefly reveals the casting of the spell), etc. This can be alleviated by taking one full round per each (or two) spell level(s) to cast the spell. This adds a bit of drama to casting, as rarely does combat allow for prolonged casting, and buffing is harder to prepare if it takes over long. They can take the chance - but it may have an unanticipated and even unwanted effect.
Lastly, some DMs will rearrange which spells are in which schools or may completely remake the schools. (For example, consider the Colors of Magic series, which removed the traditional 8 schools in favor of about a dozen color based schools.) Something as minor as this - by itself - can have a notable impact on the game.
Does any of this help?