As Dyflam so kindly pointed out, you can get great starter plants from Exotic Gardens, sponsors of this site. *VFTs are great plants. *You CAN put them in a terrarium but its not necessary to grow them and as many have pointed out, they do best outside as nature intended. *Tropical sundews will do well in a terrarium...pinguicula too (they stay small and won't grow out of a tank). *Just make sure you don't mix temperate plants with tropicals or you will have dormancy headaches. *Neps do well in tanks until they outgrow them.
Substrate would be as deep as a pot if you were growing them potted. *In fact, some people keep their plants in pots, but sink the pots in substrate so that the plants can be removed easily if necessary (dormancy, pests, etc.).
I use a mix of cool white and GroLux fluorescent tubes over my tanks left on for at least 14 hours (on a timer). *You do not want to completely seal a tank as you need some air circulation to keep mold and fungus at bay.
As far as growing conditions go...different plants have different needs. *Its a good idea to read up on the native conditions of the plants you are interested in and then try to duplicate that (temps, water, humidity, light) in your own setting. Also there are many different ways to grow CPs and everybody experiments to find what works well for them in their environment.
AND...Welcome to the forums and a very addicting hobby! *[img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img]