Pawns are almost always better placed on squares of different color than your bishop. If you have both bishops (or no bishops), then the choice depends on other factors in the position.
With pawns on dark squares, your light-squared bishop will have plenty of room to maneuver around; it is key to not have any impediments when you are trying to achieve active pieces.
There is one exception to this rule. When you have a light-squared bishop, it is acceptable to place your pawns on light squares under the condition that the bishop is outside of the pawn chain.
During endgames, the situation changes slightly. Unfortunately, it is difficult to make generalizations about endgames. Sometimes it will be proper to play for a draw in which case it is probably correct to keep your pawns on the same color as those which your bishop uses to travel the board.
Next time you go to push a pawn, remember to consider your minor pieces first.
White to mate in two moves.