There are many games with this material imbalance, so it is important to know the basic strategy in such situations. Broadly speaking we can divide into two parts, middle game strategy and endgame strategy.
In the middle game two minor pieces tend to be stronger than the rook and pawn as the rook won’t be able to find open lines. Therefore in the middle game player with two minor pieces should attack with his extra piece, as in the following instructive example.
On the other hand the player with the rook and pawn should look for an endgame where his opponent does not have a single major piece on the board. In such cases the availability of a passed pawn and targets matters a lot and if the rook is able to access the targets it can often win. Here are a few examples:
A) Rook and pawn vs. two knights but the rook fails to find targets
B) Rook and pawn vs. two knights – the rook wins
Here all Black’s pawns are weak and so White’s rook can target them easily:
C) Rook and pawn vs. bishop and knight – the rook can’t find a target
D) Rook and pawn vs. bishop and knight – the rook wins
There are of course exceptions to these situations, but generally speaking the rook and pawn are better in endgames.