re: Poker & How will i avoid beaten on the river ?
If your playing good cards and your opponent is hitting there Straight or Flush on the river to beat your 2 pair or set then you need to pay more attention to the board.
What kind of drawing hand could they be on?
Are they already on a made hand?
If you think they are on a drawing hand make them pay over pot odds
to make the call, any decent player will fold to you, your probally not pushing them enought to get them to fold there draw's.
If they already have a made hand then you will have to judge for yourself if your in the lead, but dont put to much faith in average hands that is just asking to be rivered.