Heads Up Strategy
In a heads up match, you need to quickly categorize your opponent. They will usually fall in to one of three categories.
Category A: Weak/Tight This player will call a lot of big blinds and hardly ever raise. They want to see all the cards before putting much in to the pot. When they do raise you should fold unless you have the nuts. There will just be way too many opportunities to buy pot after pot to take any chance when they raise a hand. The one trick this player will employ is a check raise; again be prepared to get away from a mediocre hand. Their big hands will be few and far between and the blind increases are in your favor as you continue to pick up the easy pots. Do not let this player see cards for free. You can literally suck the wind out of these player's sails and watch them flail about in agony. The one adjustment you will need to make is when you get them to the desperation point, be careful not to double them up too easily. Avoid winner's tilt when you have them down and finish them off properly.
Category B: Tight/Aggressive This is a tougher opponent typically but you can still keep them off balance with some strange manuevers. They will usually be trying to put you on a hand, so vary your play to keep them off balance. They will still play too narrow a range of hands usually so you can still pick them apart. Look for suttle differences in their bets on strong vs. weak hands; a lot of times they will value bet their big hands to get more chips and overbet small strength to try to take it down or gain information early. If you can detect just one or two weaknesses early, they will make all the difference as the blinds increase. If they raise 3 times the blind on their good starting hands, offset this by raising 3 1/2 to 4 on yours. Don't get caught up in a battle with them. Learn to feel pressure and avoid it. They will take the lead when they feel they are ahead so you can learn to feel the pressure and gauge their hands by it. Throw in a weird amount once or twice for no reason making sure to keep this random. While it will be random to you, it will mean something to them so be wary not to induce the wrong play.
Category C: Loose/Aggressive This player is just practically asking you to take their chips, but do not get too loose early on. They are king of the coin flip and that's actually their best weapon as they are usually not a strong player post-flop and will try to bluff at just the wrong times. Be prepared to hear how bad their luck has been running that day if you "suck out" on them. They will give you action when you want it so don't get sucked in to playing like them. This player will usually assume that you play like them so if you bet big on the end they will think you are buying a hand and you can get some calls most people wouldn't give you, so don't be afraid to get your chips in on your big hands. Don't get too fancy; they aren't going to notice or fall for anything. Straight up is the way to beat this player. Expect a large variance swing at times against these players but play correctly and in the long run you should win out.
Those three categories will be your normal opponents you will face, and you should be able to learn to beat all of them the majority of the time. Remember there will be lots of variance heads up, so you may have to play a few hundred games against each type of opponent to see a substantial gain in bankroll.
The most fun heads up matches will not be the most profitable more than likely. They will be the few times you line up against someone who has the ability to adjust to your game. You will know when you are against a tough foe. It will wear you out and even if you win you will feel like you got kicked all over the felt. Out of the hundreds of heads up matches I have played, I can only think of about 4 players that I really felt had an edge on me. I learned something new from each of these individual's style of heads up play and added it to my arsenal. I am confident that you can learn to be a strong heads up player. Don't be discouraged if you aren't where you want to be in this part of your game. With practice, it's truly one of the most rewarding and fulfilling parts of poker.