It's best to read up on the supplies and how-to's 
first, and two of the best links have already 
been given. ^_^ Go ahead and give it a try cold, 
and see where your strengths and weaknesses lie. 
Are you happy with the acetate you use? Are you 
happy with your ink? Are you happy with your 
paint?

For instance, with my first try, I used a 
particular kind of acetate that had been treated 
in some way that it didn't want to let the paint 
sit on it-- and so my paint would severely crack. 
But because I had tried it on my own first, I was 
able to focus my discussions with people on 
whether or not that problem had ever happened to 
them, and if it had, how they had resolved it.

Once you've done some firsthand experience, you 
might start talking to other fancel artists and 
compare results. Most are probably more than 
happy to chitchat about their personal 
preferences (ie, ink brands, paint brands, ink-
under-the-paint versus lines-and-paint-on-
opposite-sides, acetate thickness, etc). But it's 
good to give it an educated try first, so that 
when you have discussions with people, you have 
context in which to place their recommendations, 
and have specifics you might want to query about.

Requiem has a nicely active forum where you can 
get good advice:

http://pub36.bravenet.com/forum/show.php?
usernum=3087734918&cpv=1

and 

http://www.ringsurf.com/netring?
ring=FancelArtists;action=list

is a ring of fancel artists you might browse and 
maybe talk to.

Good luck!
-Cres