Welcome to NP
Try and avoid obscure, strange extension with very little sales history like .BZ. Belize has a population of around 350,000, not much of an end-user market there.
Domaining is not just about the keywords but the extension is the other 50% of the name. You will find decent single dictionary words available in some extensions, but that's because there is very little demand for the extension
Try and stick to .com names until you get a better idea of what type of names sell. Check out namebio.com and dnjournal.com to see recent sales.
Also ask yourself before registering any name "Why is this name still available with the millions of domainers and businesses out there?" the answer is usually obvious.
My advice would be to not hand register names that are available, look at expiring/dropping lists or email existing owners of decent names looking for bargains. You are better off spending $200 on 1 average/decent name than $200 on 20 names that wont sell.
Good luck