Help for the Inept with Problem Hair?

Boy have I got some problem hair on me, if I went into detail it would be a novel. What has me most concerned is that it seems to be getting thin on top. No bald spots or anything, just thinner than it used to be. I don't keep it in tight ponytails or braids or anything that would be pulling it out.It is dark brown, getting pretty gray (I get it colored when I have a good reason to, maybe once or twice a year, otherwise I just let the gray grow out), length - about down to bra strap level, bangs in front. It's got a natural wave to it, if I dry it right (scrunching it, which I don't do very well yet, I'm new at this). Over the last few months it's turned into oily hair for some reason. Before that, it was dry hair. All my life I've gotten the "WOW do you have thick hair" comments, but as I said, it's getting thinner.I don't use any mechanical gadgets on it because I'm all thumbs with that stuff, but I did just order a blow dryer with a diffuser (with those finger thingies) because they used one on me last time I got my hair colored, and it got all curly & looked really cool. When it arrives, I'll see if I'm as klutzy with it as I usually am with these devices, I hope not.I don't put any gook in it usually, either. At the aforementioned salon, they gave me this conditioner to rub into it, and then scrunch it up while it dries to get that curly look, but I haven't been very successful so far at achieving that. I tried some mousse stuff a few times, but it made it all stiff.I wash it whenever I can, but not as often as I would like. Because of strange living conditions, I don't have access to running water on demand, and usually all I can get is cold water. A few times a month, I can get a good hot shower, the rest of the time it's garden hose or nuttin'Anyway, any suggestions are welcome. I haven't cared too much about my hair for some years, but now I have a reason to, and I want it to look nice! It is probably obvious by now that I have no idea what I'm doing here.THANKS!