Any tips or guides for painting? I'd like to build a Tau or CSM army, but I'm ass at painting.

And isn't this the dude who loots shit from history and keeps it his own little museum?

Pay me to do it ;DDDDD

In all seriousness, there's actually kind of a lot to explain about painting models. There are plenty of video guides on Youtube, though I tend to not watch those, as they make me feel super insecure about my own painting. I guess that the most simple things I can tell you is to almost always work in kind of an assembly-line structure. Base, wash, clean, highlight. Washes alone make all your models look infinitely better, so be stocked up on Nuln Oil, Druchii Violet, and Seraphim Sepia. Druchii is like the ranch dressing of paints, it improves almost any color on which you use it. I use it to shade reds, pinks, some blues, unusual greens, pale fleshtones, ect.

It also helps to have your models partially-unassembled before you paint. At least make sure no one's holding a two-handed gun when you start painting, pistols and swords are fine, just nothing that covers their chest.

Oh yeah, and prime your models. Acrylics don't bind to plastic, you can rub it off with your thumb in most cases. I swear by Krylon ultra flat grey PRIMER (not paint+primer) spray cans. Use black if you're painting a black army, use white if you're painting white/yellow/pink, use grey for every other color.

Honestly, if I'm dropping the dosh to make a full army, I'd totally commission you. Your noise marines looked pretty good, and because I'm a degenerate Slaanesh worshipper. ( and the commie space weebs) I'd totally be game for that. I'll practice, but I'll probably commission the first army I get.

I even work on a model-to-model basis, so even if you just wanted something cheap, I can do most HQ's for $30-40, and I usually recommend that option as a test model to prospective buyers.

Oh yeah for sure. It's definitely somthing I have to build up. Question though, don't the CSM have a bad codex? Even more on the Slaanesh side?

Well...what the CSM have is a very balanced codex in a very unbalanced game, basically. If you play casual games, you're fine. I play strictly Tzeentch (easily the worst god in the book, rule-wise), and still win most of my games through tactics and heavy use of flamers. The CSM are basically overpriced for what they do, in general. Regular marines cost the same as loyalist space marines, but don't get things like Chapter Tactics, Combat Squads, or And They Shall Know No Fear. But, I still think CSM are fun, I'm just not gonna' take my Thousand Sons to any tournaments.
Slaanesh is actually probably the best, or second-best, in the CSM codex. He has possibly the best psychic discipline, and his mark is arguably more useful than Khorne's, since the mark of Khorne stops being useful after the first turn in any close-combat.

True, I'll have to pour over the rules and such for the factions. I've got the gist of them, but I'm still working on the rules and number and stuff of the game. As I know the lore and fluff super well, but only kinda sorta with the rules.

I'd recommend Daemon allies for chaos marines. Daemons summoning more daemons is a pain in the butt and very effective in objective based games. One of my regular opponents uses this with Space Wolves (???-don't ask me-he's super cheesy). He drop pods in a load of space wolf stuff and charges across the board with a bunch of thunder wolves. I HAVE to deal with this stuff. Meanwhile his daemonic allies are summoning more and more units. It's tough to deal with. I expect you could do the same with chaos marines (and it'd make a lot more sense thematically vs his Space Wolf/Daemon nonsense ;)).
I think a new edition of 40k is not too far off-so maybe the dynamics of the chaos marines will change a bit?

But my precious noise marines. How will I please the god of sex, drugs , and rock & roll, with out my bass cannons? :,V

Take Slaanesh chaos space marines with daemon groupies :) A few daemon allies added to a mostly chaos marine list will make it far more effective and let it compete with tougher forces without compromising the theme :) Daemonettes, a Daemon Prince and maybe some seekers? I'm not an expert on chaos, but the ability to summon is very useful (so give the daemon prince/princess that ability) :)