A few suggestions:
1. READ THE SPELLS IN THE PHBII. They are AMAZING! They are NOT listed in the Spell Compendium and many people do not know about them. Pay special attention to spells that are immediate actions (can occur during other people's turns). Certain spells I like: Chain Dispell (8th level spell, max CL 25, and 1 target/level) Greater Celerity (as an immediate action, take a full round action and then you are dazed for the next round.
A little more on Greater Celerity - short of wish/timestop, this is perhaps the best wizard spell in the game. It enables you to prevent things from happening. The BBEG about to cut the head off of the princess? During his turn, as the sword starts to descend on her neck, you cast celerity. You then Stroll over, cast a prismatic sphere around her (or one of your veils), spend the next round safely inside, then explain to her what is going on and take out the BBEG. Is the God you are fighting about to remove you from existence with mass life and death? (your foresight warns you) you cast Greater Celerity and dimension hop out of his range. Is the [thing that cannot happen] about to happen on somebody else's initiative? Cast Greater Celerity and stop it.
2. I know you want flyby attack to attempt to use your veils for cover. Don't. It will only encourage your enemies to find ways to neutralize your veils and/or focus on you. (e.g., a readied action to grab you when you pop through to the other side) Use that feat to be better at offense, or to better specialize at something. A better feat, if you have access to the Complete Adventurer, which would allow you to do the same thing is: Mobile Spellcasting. With a concentration check DC = 20 + spell level, you can move AND cast as a standard action. In other words, since you can take a move action and a standard action each round, with this feat you can: 1. Move to the other side of your veil, 2. cast your spell, and the 3. move back behind your veil. Being able to perform your 'attack' action and to take a double move is rather rare in 3.5, and it should allow you to put some distance between you and the guys with the swords.
Combine Mobile Spellcasting with Celerity and you have control of the battlefield.
3. If you want to be VERY effective at one thing, spend your feats on it. For example, choose a spell (e.g., Orb of Force), take it as your arcane thesis, take a metamagic feat that you want to effect it with (Twin Spell & Quicken spell), take Residual Magic (my favorite feat) and have at it: Round 1: You cast a twined orb of force (level 7 spell) and a quickened orb of force (level 7 Spell), Round 2: You cast a twined orb of force (level 4 spell, metamagic free from residual magic) and another quickened orb of force (level 7 spell). You've now done, in 2 rounds, 60d6 damage with no save.
A quick word on Residual Magic. It is Amazing. It allows you to apply a metamagic feat to a spell for free if you cast that same spell modified by the metamagic feat last round. I like to do a few combos with this: Use arcane thesis to reduce the meta magic cost, use metamagic school focus (not sure if that is what it is called)to reduce it by 1 further 3 times per day. Then, use residual magic to allow you to get 2 uses from each metamagic reduction. EG: You have spell focus Abjuration, metamagic school focus abjuration, repeat spell, residual magic and arcane thesis: Chain dispell. You memorize a repeat spell Chain Dispell in your 9th level slot and a standard chain dispell in your 8th level slot. Round 1: you cast a repeating chain dispell. Round 2: your repeating dispell goes off, then you cast another chain dispell and automatically apply repeat spell through residual magic, Round 3: your second repeating dispell goes off and you can take a standard action. This combo has allowed you to cast 4 8th level spells for an 8th and a 9th level slot.
Other uses of Residual Magic: Abusing Sudden Maximize/empower/quicken. Round 1: You cast a sudden maximized Meteor Swarm, Round 2: you cast another Meteor Swarm and Maximize it for free.
Other interesting combos are to use Arcane thesis to add a bunch of +1 spell slot adjustments to your thesis spell for free:
EG, you choose Fireball and take Sculpt spell, still spell, silent spell, and enlarge spell. From now on, all of your fireballs, without level adjustment, are stilled, silented, sculpted and enlarged.
Other interesting metamagic combos: using arcane thesis for fireball, take explosive spell and widen spell. For a 6th level spell slot, you get a double sized fireball that pushes the targets to the edge, possibly knocks them down, and does extra damage to them. (Explosive spell is GREAT!)
If you just want to deal uber damage: try these feats: Energy Admixture or Twin spell + arcane thesis + Metamagic School Focus = a ton of damage. EG: 8th level Delayed blast fireballs that deal 40d6 damage.
There is also a Scorching ray build, where you basically focus on casting scorching ray with a ton of metamagic feats added onto it to make it deal uber damage to a single target.
Also, Split ray is a really nice feat - +2 spell slots to double the effect of a ray spell.
