Agree with billryan about new machines. When Walking Dead first came out everybody pounced on it and won lots, you could hardly get on one. Then they seemed to go really dead. Now they have a new version(s) of Walking Dead and everyone is playing it. In due time it will poop out. Same for the Buffalos, got new "Grand", "Gold" Buffalo etc. If you play one of those and get a good hit, RUN AWAY. Of course that applies to any slot. But they make lots of noise and are entertaining, until they suddenly start sucking your money away.
I had a good run of luck on a new "Aladdin" machine at Beau Rivage, but my friend playing next to me didn't do much. You have to get the bonus round to do anything.
Dragon machines (Dragon Spin, Dragon Rising, other dragon types) seem popular right now. Depends on when the casino, wherever you are, installed them.
Somehow I always seem to get early hits on Pinball. But I've learned to hit and run on those.
I thought Rolling Stones would be good, but I have never seen it hit much. Celebrity machines don't do much for me, though my friend did well on Ellen at Wynn some time back.
I think Sex and the City is dead everywhere. It was fun for a while.
Look for Quick Hit progressive games (all kinds) that have a separate "Bonus" box at the top. Those Bonuses reset at $100, climb progressively and hit fairly often, and you get that full Bonus even if you play the lowest coin.
I see people play that Fu Da We or something like that. (Chinese babies that giggle a lot) It takes $8.88 to play full coin, but most people play it low coin and get lots of bonus rounds (time playing, not big money) and it has that top Bonus progressive box also, I think I remember. I don't play them but everybody else seems to.
Good luck.