i have 12 lb test fluorocarbon with like a diameter of .29mm, should i put on a swivel and put on some lighter line so the bass wont see it, will it enhance the chances of a strike and make bass less aware?

You'll be fine with just the 12lb fluoro. 

Many people tie braid direct with no leader and are successful, I don't think it makes much difference, whatever you are comfortable with.  I use a leader but never saw any difference in freshwater fishing using florocarbon leaders.

i would not use a leader with 12lb flouro.

if you did use a leader you'd want to tie the lines directly to each other and skip the swivel.

i use the albright knot:

http://www.animatedknots.com/indexfishing.php?LogoImage=LogoGrog.jpg&Website=www.animatedknots.com

alberto's knot is said to be stronger, i havent tried it yet:

http://www.stripersonline.com/Pages/Articles/article_arby_albertos_knot.shtml

No you shouldn't.

Nope you shouldn't.  If you are fishing ultra clear open water and feel like you want lighter line I'd suggest going to 6 or 8lb floro on spinning gear.  There are times when this will get you more bites but I don't like to go that light around any cover.

Why did you choose the 12# fluorocarbon?

Whats your main line? I assume braid correct?