Do lots of no stirrups to strengthen you legs. It will also improve your position!!
Riding without stirrups for at least five minutes each ride.
Make sure ur heels r down and if they are start doing some leg workouts
When I started horse riding I was exactly the same but my teacher said to squeze your legs against the belly of the horse,that's what my teacher to,d me anyway ;)
try trotting without sturrips
I practiced a lot in my half seat to get my legs down and around the horse. It helped strengthen my legs and correct my leg problems! Do it in trot especially!
My horse has a very very jerky trot and not a very smooth canter, thinking this could be some of the problem. Are there things j can do to stop it??