Once you get into the more obscure extensions - small island countries, .name and so on, there are a lot of LLL and even some LLs left. Mostly because there is nobody who wants it. Plus many of these extensions are expensive.
There are LLLL.net and .mobi left that could be worthwhile - the .mobi is a long term play that has more risk than other possibilities, and the .nets have been picked over pretty well. Both I would consider to be more for those with experience who can see possibilities that others would miss.
The best thing to do is to spend time reading on this forum - a lot of time. The more you know the better your purchases will be. I have been doing this for two years and every few months I still find an important improvement in how I do things that adds, say 25% to my purchases' value.
Probably the best area today for the beginner is 5 letter.coms. There are several threads in this section for you to study - I would watch the drops and buy only easily pronounceable domains - emphasis on the easily - that you can see a company wanting for their brand. There are over 17 million possible LLLLL.coms, buying randomly would only waste your money. Go slow.
What's the last improvement that you learned?
