A jab can be very difficult to get by if your opponent knows how to use it. Keeping your hands up is not the trick at all because a good boxer will actually stop you in your tracks with their jab. I am 5'9" myself and regularly spar with a guy who is 6'5". Here are my tips (minus what has aleardy been mentioned) on how to best get in. These are geared towards times when you have a great height difference such as in my case. 1. When fighting someone of similar height to yourself, you are able to stay just out of punching range and enter the range to strike. A taller opponent has a much greater range than you. If you stay out of their range and enter to strike, you will still be out of your range by the end of your lunge. Taking mutliple steps to get in takes too long and should not work against a decent opponent. Therefore, when at a great height disadvantage, stay within your opponent's punching range, but still just outside of yours. Staying outside of your own punching range means that you are only within range for your opponent to throw jabs and crosses without advancing. Rely on a solid defense to perry all of the jabs, and when the cross comes, perry/slip it and lunge in. Entering off of a jab may result in you getting caught with a good cross and taking a fall. If your opponent advances before you do, to throw a hook or uppercut, advance yourself simultaneously. 2. When you go in, forget striking the head! The distance from you to your taller opponent's head is greater than the distance from you to your taller opponent's body. Since you are trying to overcome the distance caused by the taller opponent, don't add to the problem by going for the more distant target right away. Go for the body. Anyone with boxing experience knows that body shots hurt! After at least two shots to the body, let the combinations flow naturally. If your opponent steps back and you chase him, be careful it is not a trap! 3. Fake! Feigning strikes should be every bit as common as real punching. It should be nothing special, especially against a taller opponent. Feigns will distract your opponent while you get in, and also create many openings. Before you even think about fighting a taller opponent, work relentlessly at developing a rock solid defense! Good luck!