In reply to climber007:
To OP I'm 5'5" other than general technique as posted by others some specific things to train and think about.
Mantels: On slabs and vertical walls you can mantel the hold so that your weight is centered above the hand pushing down and locked off the hold. Keep this balance and reach up with the other hand. You'll be surprised how small or thin a hold you can do this on.
Hip flexibility:
If you have the hip flexibility being smaller will allow you to compress more, this will allow you to use higher foot holds. It's quite a strong move. If the hold is about waist level you can use your foot like a bat and hook the top of your toes on the hold with the knee pointing down
Different hand grips.
As other posters have mentioned using the holds as sidepulls and underclings will extend your reach (in conjunction with an appropriate body position). Most of us naturally climb using holds in a straight down manner, learn to use holds in differing ways so these ways becomes natural. Engage your thumb, for example on underclings you can use your thumb on the outside to give you a stronger grip.
Smearing.
From school physics lessons friction is proportional to the normal force (i.e. force at 90 degrees to the surface) so when smearing push directly into the sureface. Also the more rubber you keep in contact with the surface the greater the friction you will get from your shoe. Good ankle flexibility will allow you to keep your heels down as you reach up for the next hold. If you find that you do raise your heel when reaching up push harder with the remainder of the rubber that is in contact. Similarly if your foot starts to slip push harder to arrest the slipping.
Dynoing or jumping.
This is composed of 2 parts, generating the push and latching the hold. Being able to latch the hold is sometimes called contact strength and is the ability to grasp a hold with maximum strength "on contact."
Exercise 4 from this link
http://www.nicros.com/training/articles/top-5-finger-strength-training-exer... "4. Feet-on Lunging Exercises" is a good skills focused training exercise