As a disclaimer I'm 6'3" so this isn't from experience!
As a tall climber you're correct, I have a lot of advantages. Reach can be very advantageous, especially on bouldering.
In my experience the disadvantages of me being tall (therefore the advantages of being shorter!) are:
- I have a longer reach but I also have longer levers. This means I
find certain power moves more difficult.
- Taller people tend not to be as powerfully built as shorter climbers so again I'm maybe lacking in sheer strength (to weight) sometimes
- I find close claustrophobic moves difficult. My elbows and knees can get in the way. Shorter climbers often find these moves easier as they are in more natural positions for them
As a shorter climber you need to train for your advantages. So train for power moves. Use your lighter weight and shorter levers to perform dynamic moves. This also has the advantages of allowing you to reach the longer moves that you may struggle with.
Most important is technique. A climber with good technique will out climb any climber with worse technique, regardless of physical features. There are lots and lots of examples of brilliant short climbers The legend that is Joe brown was well known as a short powerfully built man.
I wouldn't say a shorter climber should train much different to a taller climber. A shorter climber will often simply need a different Beta to a taller climber, i.e. a more dynamic move to reach the holds, different foot positions, etc.
I'm a firm believer that the best training is climbing. So stick at it. Try some dynamic jump moves and practice them, use this to help you out of sticky situations. Work on your grip strength (dead hangs, etc.) but I would recommend this to anyone climbing short or tall.
I climb with a guy who's better than me. He's also a lot shorter than me. It really annoys him when I can just reach something that he can't. But 9 times out of 10 he'll climb stuff I can't. That is simply because he's better and height is almost irrelevant. So don't let height be a disadvantage. Keep practising and getting better and it will become less and less of an issue.