Hi, I'm pretty new to domaining too, but I bought and sold (totally) more than 15 domains now and have learnt from my mistakes.
If you're interested in keyword-oriented domains, try to only go for 2-word domains; try to avoid the 3-word ones. I would say 12 characters max is good. And I'm not saying all 3-word domains are bad - there could be great ones. Example: HotelsInCalifornia.com However, still, I'm not a fan of 3-word domains. Most of them aren't as easy to sell.
PM me, we can talk more.