All great advice. The way I approach liveaboard is a little different. If you want to wait 3 years, you can. Or, you can just do it another way.

First, I look to see if a marina allows liveaboard to begin with. If they do, I check out the surrounding area to see what the amenities are. Is there a beach for my dogs? A restaurant for when I'm feeling lazy and don't want to cook? Are the grounds kept up? Are the docks falling apart? Etc. If I like it and the liveaboard fee is reasonable, I move my boat there. Pay the bills, work on your boat, don't be loud or have parties, be friendly, etc. After a few months, ask for liveaboard. 100% of the time I was given liveaboard when I asked.

I would purchase a boat first before moving onto it. If you want advice for what to look for, as others said go see as many boats as possible. Talk to the owners, neighbors, etc. Stalk YachtWorld and you'll have a better idea of what you want for your needs.

Good luck!