Match play differs from stroke or medal play because the match is decided on a hole-by-hole basis. If player A shoots a 4 on the first hole and player B shoots a 7, player A is plus-one on the scorecard. If player B shoots a 3 on the second hole and player A shoots a 4, the match is now even. Even though player A won his hold by three strokes and play B won his by a single shot, the stroke differential does not matter. This allows the golfer to put bad holes in the rear view mirror. That's the big difference between stroke and match play.
When you win a hole, you have played well enough that you should be able to take that confidence with you on the next hole. Remember what you did right and why you won the hole. If it was a long putt, bring that with you and know that you can sink another long one on the next hole. Also, your opponent may start to press after losing a hole. Take a lesson from that and realize that golf is a stroke-by-stroke game--you can't look back and you can't play ahead. The only thing you can do is concentrate on the next shot. Match play, as opposed to stroke play, lends itself to this kind of thinking because each new hole represents a major opportunity to turn the tide of the match.
If you are playing a golfer who is better than you are, you might not be able to come within four strokes of him in a medal play match. Your opponent may beat you by two or three strokes on certain holes. The fact that it will not give him any extra advantage works in your favor. Having two or three poor holes is not going to matter. If you can put those holes behind, you should be able to compete and possibly pull the upset.