In case you don't know, BMX tracks are dirt courses where races are held. The track can be indoors or out. Some are free to ride on, while others require a membership or something like that. The free ones are preferable, but the ones that require money are usually nicer.
What quality of dirt is it? It should be dark to medium brown, well packed, and with no dirt-clods. If the dirt is light and powdery, a crash is imminent.
How many different types of obstacles(jumps, berms, etc...)? At least 5 different obstacles. If there is less the jumps become monotonous.
Where is it located? That all depends on what kind of competition you want. If you are looking for some stiff competition then a major city is your place to be, more people = more competition. However if you just want to have fun a small town is your ticket because there is less people.
Is there a concession stand? Hopefully, if there isn't then that means that there isn't enough business.
Are there sponsors? There should be sponsor banners posted around the track.
Does the track have a starting gate? Yes definitely, every good BMX track should have a starting gate. A starting gate keeps all the riders contained until the "go" signal.
If the track you are at has most of these things, then its time for the next step,identifying jumps.
Always wear a bike helmet and keep an eye out for these safety Hazards: