Illusionist/cleric build help

[Legendairy]

Hey all,

One of my players is playing a whisper gnome illusionist/cleric I don't know much of what he has now. He is wanting help with the build, I know he currently has Silent Spell as one of his feats and is playing up the sneaky illusionist type. He will be going into mystic theurge Prc when he can. What I'm asking for is a list of feats that would make this build awesome as of now it's just mediocre at best. Thank you all

[Gandariel]

First level of Sorcerer, take Practiced Spellcaster: this makes you able to enter the class one level before the others..

[Legendairy]

He's already level 3 and went Mage(illusionist)/cleric

[Biffoniacus_Furiou]

The strongest choice for an illusionist, particularly a gnome, is to take Shadowcraft Mage from Races of Stone. Use Heighten Spell with Silent Image to mimic evocation and conjuration spells, and use Earth Spell (RoS) with sandals made from stone slabs to significantly increase your caster level for those. Get Residual Magic (CM) so every other spell you cast is heightened for free. Multiclassing is a really bad choice for any caster, so pick a class and stick with it.

For Cleric, use Cloistered Cleric (http://www.d20srd.org/srd/variant/classes/variantCharacterClasses.htm#clericVariantCloistere dCleric) with the Gnome and Illusion domains, with the PH2 spontaneous domain casting ACF for one of those. Get DMM: Heighten and qualify early for Shadowcraft Mage via Heightened Dark Way.

For Wizard, go Wizard 3/ Master Specialist (CM) 4/ Shadowcraft Mage, use all of the UA Illusionist ACFs (http://www.d20srd.org/srd/variant/classes/specialistWizardVariants.htm#illusionistVariants), take the Gnome Wizard 1 substitution level (RoS), and get Signature Spell (PGtF) for Silent Image.

[Legendairy]

All sound like amazing options again unfortunatly he has already made the character and is level 3. cleric 2 Mage 1 and has silent spell so far just need further options and he still plans on going theurge. Feats and build improvements.

[Olo Demonsbane]

Have him grab Sanctum Spell as his third level feat so he can start going Mystic Theurge next level and not completely suck.