A - Players usually want to have sex without any commitment.
B - Players are usually willing to spend money and sweet words on you, but time and sacrifice are the bane of players. Time and sacrifice for a loved one cannot be faked, and there are no refunds. Usually a player is willing to spend a little bit of these in order to sack a very beautiful woman, but they will only go so far, find that limit.
C - Take into account his history if you can. People rarely change, especially at your age. If they were a player to women before, they'll most likely be a player now.
You can't recognize a really good player, you'll be in his bed by the time you figure it out. A bad player, well they're easy to spot, they turn you off, creepy, try hards. But your intuition goes a long way, you should quiet your mind and look inside to see how you feel about someone, if you sense something off, then their probably is.