[4WheelVFR]

As far as setups go, I would definitely recommend live plants, even for a newbie. There are many very easy to keep plants out there and they definitely have their benefits in an aquarium. As far as fish go, a great starter community for a 30 or 40 gallon tank would be a small school of tetras (many different species), a small school of corydoras catfish, a plecostomus (just be careful what species as many get very large) and a pair of small cichlids such as Apistogrammas. There are also many native fish that would work well in that type of community. Really, there is an unlimited choice of fish to choose from.

As far as compatibility goes, that can be a crapshoot sometimes, but the first rule of thumb is that if it can fit in another fishes mouth, it will end up there. If you have any idea of fish you want to keep, I can help give you ideas of what suitable tankmates would be.

As far as the nitrogen cycle goes, i've never paid it much mind lol. Just add fish slowly to a new setup and they should be fine. Don't overstock and don't add too many fish at once and they should be fine. The nitrogen/ammonia cycle is very important to understand, so I do recommend you read up on it if you already haven't.

A couple very important rules:
Only feed what your fish can consume in a couple minutes, once or twice a day.

Once a week, siphon out 10% of your aquarium water along with any stuff your siphon picks up, and replace it with fresh, dechlorinated water. Water changes should be mandatory and 10% to 25% a week is a good number.

Hope this helps a little bit. I'll also post up some links of mine for you to go over.