All right I've played as a pure thief,pure warror,pure mage now I want to mix it up some.
Stealth is by far my favorite way to play,but this time I want to add some magick.

Mostly I'll be useing Illusion,Alteration,Stealth,Dual wielding daggers,Pickpocket and maybe some Archery.
Any tips would be appreciated as I have yet to mix magick with stealth.

What Illusion spells other than muffle and invisibility should I get.
Also I will probably wear light armor but won't be perking it,so I will probably be a little weak when discovered.I like the fragile glass cannon type stealth characters.
This will also be my first run on expert difficulty.

One last thing I am going to be an Argonian this time around as they seem kind of rogueish and I haven't played an argonian yet.

Any advice?

Edit:I really like Alchemy for my archer characters but would it really be worth it when dual wielding?
Also I was just thinking since I haven't tried enchanting yet I might add that in as well or am I starting to spread myself too thin.

Well, all the behavior control type spells are great. Calm, Fear, and Frenzy will all help you escape when you're discovered.

For Illusion, try calming spells. They fit a rogue well, and can get you out of some nasty situations.
Alchemy is always worth it, poisons are awesome, no matter what's your main offensive skill.
Enchanting is optional. You don't have to try and have too many skills, it's better to concentrate on just a few.

Yeah I was thinking,enchanting doesn't sound very rogueish where as poisons do.
Alchemy will also free up a couple of perks to use elsewhere.

For escaping: Invisibility and Quiet Casting with Kindred Mage should get you out of trouble. Shadow Warrior will usu serve the same purpose. It depends upon how you want to allocate your perks. I have both (well, all 4) at 70 and both techniques work equally well if you have enough Magicka or Fortify Illusion gear.

I prefer Enchanting over Alchemy if I had to choose only one path, but I also Smith my armor past the armor cap because I'd rather put enchants on the armor than pop pots and cast spells all the time. I mainly do the Smithing because I only wear leather-based armor and sometimes I get a little too impatient and just want to slash up the enemies plus dragons are difficult to use stealth on. Most of the time I act as a proper assassin though.

I leveled Alchemy to 100 and got all the beneficial perks so I could make powerful Fortify Smithing potions relative to what I said above because there's no perk associated with leather-based armors. I've never seen a use for poisons because with the Backstab and Assassin's Blade perks coupled with the DB armor I could 1-shot Sneak Attack anything. That may be too over-powered for you so be warned: I could 1-shot Dragon Priests long before I hit my current level of 70.

I don't use archery other than to annoy dragons until they land, but I know this: if you want Archery to be useful you're gonna' want to assess some perk points because mine is really weak even with Legendary Ebony Bow and Daedric arrows.

One of my favorite character types, you'll enjoy it. Get Illusion Dual Casting and then buy a Rage spell, and later on Frenzy when your skill level and funds permit. Works perfectly for a stealthy mage/archer, you can sneak around and Frenzy large groups into thinning their own numbers, and then mop up the rest with some long range sniping. I'd take a little bit of Conjuration as well for some on-demand muscle when you get rushed, but it's not required if you don't want to bother. Properly perked up a dual cast Frenzy works on any NPC/creature in the game that is not outright immune to the effect (such as undead before the perk), it's all you'll need to control the battlefield.

Do I need the muffle perk from the sneak skill if I have the muffle spell?
I was thinking of not going up the left side of the sneak tree at all since I will be doing quite a bit of illusion.

They're both 50% Muffle but even with a lot of illusion, a lot of the later Sneak skills up that left side are extremely powerful. Silence provides 100% Muffle no matter what speed you move at, Light Foot is pretty keen since triggering a trap can give you away, and even Shadow Warrior is useful if you're out in the daylight or your ambush goes awry.

I've never used the spell. I only ever used Muffled Movement and 4 pieces of +40% Fortify Sneak gear and enemies bump into me and keep going all the time. I'm guessing the numbers for how much is muffled that are reported are from looking at something in the consoles of the PC because the only number I see is in the Muffled Movement Perk.

Sounds like what I'm doing atm. I would get illusion dual casting as soon as possible, because you can cast spells onto higher level enemies than just single casting.

Also, draugr are a nightmare on that build until you find a bow and dagger with a turn undead enchant. I don't do any smithing or soul trapping, so I've gone heavily into the Speech skill on my rogue, I can afford to buy filled gems and the only time I raise enchanting is when I charge my weapons.

Any tips on leveling Illusion,the only spell I have enough magick to cast is fury and at level 7 now I've only been able to use it once in Bleak falls barrow.
So far though it is a fun build,sneak and one-handed are leveling very good.

Oh I just saw in another thread that the muffle spell does +1100% muffle wich seems like 1000% overkill but it sounds like it should work out well if I can get to the point were I can cast it.
Also this dual wielding daggers is great fun,it's much more satisfying to get in a sneak attack backstab than to shoot with a bow like my previous stealth characters.
I find it more fun and challenging to take my time to watch the enemies movement patterns before going in for a kill.

Yes.

Buckom,what kind of other enchantments do you use for this type of character?
If I can't get Illusion going I might go with enchanting instead.
Getting filled soul gems seems like it would be tough without conjuration also,wich I didn't want to do.

Muffle is the way to go, put on your novice hood and you'll have enough to cast. At low levels you'll a level per cast. The fast, cheap thing to do is the Illusion master's quest at the college; clean the focus and you'll have super fast regen for hours, enough to get to 90 if you have the patience. (don't buy any spells from him before the quest, it may interfere.)

I don't use weapon enchantments for 2 reasons:
1) with my Smithing maxed and using gear and potions to improve my Ebony Daggers they do 159 each 'base'.
2) I get tired of recharging weapons
Actually, I have a Daedric Dagger with Soul Trap on it that I carry, but I just equip that when I have Grand or Black Soul Gems to fill.

Primary:
Forsworn Headdress: Waterbreathing + Fortify Lockpicking
Forsworn Armor: Fortify Healing + Fortify Stamina Regen
Forsworn Gauntlets: Fortify Sneak + Fortify Lockpicking
Forsworn Boots: Resist Fire + Resist Shock
Gold Diamond Necklace: Fortify Sneak + Fortify Lockpicking
Gold Diamond Ring: Fortify Sneak + Resist Magic

Alternate:
Silver Jeweled Necklace: Resist Frost + Resist Magic
Silver Amethyst Ring: Resist Fire + Resist Shock

For Fishing Small Jobs:
TG Forsworn Gauntlets: Fortify Sneak + Fortify Pickpocket
TG Forsworn Boots: Fortify Sneak + Fortify Pickpocket
TG Necklace: Fortify Sneak + Fortify Pickpocket
TG Ring: Fortify Sneak + Fortify Pickpocket

Thanks for this it looks like your keeping it very thief like,thats what I'm looking for,I like to roleplay.

NP. Make no mistakes now: the girl can fight. I've got that armor smithed past the cap for her with her having Custom Fit and Matching Set. With the silver jewelry she can stand in the face of a dragon and slice them up before they can get back into the air. Some times I'll just hack and slash with her if it's getting late and I just want to get out of a dungeon, but most of the time I do sneak around and stalk my targets. I'll use Throw Voice to separate them and isolate the 'next' one. I've even devised a strategy when I have a noisy follower. I've been using Mjoll lately so I'll crouch (she does too), but her Sneak isn't nearly as high as mine so the NPCs will hear her, run past me to get to her and I can Sneak Attack/Backstab them as they run by me.