Strategy tips for chess are capable of filling volumes of books. If you're interested in becoming a very skilled chess player, we suggest that you seek out such books. However, here are a handful of tips:
During the early part of the game, try to control the center area of the board. Move pieces into the center, or move pieces into position to protect the pieces in the center.
The most common opening moves are to move the king's pawn or the queen's pawn two squares forward.
As you move your pawn structure forward, try to keep the row staggered, so that the pawns to the rear protect the more forward pawns.
Notice that when you use a pawn to take another piece, it leaves two of your pawns in the same column of the board, which is a weak position - the rear pawn can no longer protect the front pawn, and there is a resulting "hole" in your line of pawns that your opponent can use to threaten your more important pieces.
Don't overreach - for example, don't move your bishop into an aggressive position by itself on your opponent's half of the board, where a simple pawn move will force it to retreat. Move your forces out steadily and evenly.
Sacrifice a less important piece in order to take a more important piece of your opponent's. Generally speaking, the order of importance of pieces, from most to least important, is queen, rook, bishop, knight, pawn. Some experts consider the knight and bishop to be of about equal worth. The king is not included on this list since it can never be taken.
Move a piece so that it threatens two of your opponent's pieces at the same time. That way, whichever piece the opponent moves out of harm's way, you'll be able to take the other. This is particularly effective when one of the threatened pieces is your opponent's king, as there is no choice in this case - your opponent must get the king out of check.
Try to anticipate your opponent's best move, and plan accordingly.
Balance offense and defense - don't concentrate entirely on one, to the detriment of the other.
Don't rush your moves, but also don't fall far behind your opponent on the time clock; this could put you in a terrible time bind toward the end of the game, forcing you to make unplanned moves, or worse, making you run out of time and lose the game.