My Run Up!

hey baby!! try to run fast and with some aggression...
A. get proper cricket shoes...
B. Stop the horse strides you are taking/trying
C. start casual, accelerate as you go, but not as if in a 100M sprint, just run smooth, and deliver the ball...
D. make it a straight run, since you are a young chap, avoid side on
E. practice practice and practice...
F. Take a front on and rear view video next time, to proper gauge your improvements or short falls...

hope this helps...
I am mostly a batsman so I have a pair of Lunar Dominate shoes and we play on astro turf and sometimes turf so I use a shoes popular in South India called V Cricket shoes. What do you mean by the horse strides? Also I got used to Side on so I can't adapt to front on. :(
The side on is fine, if your comfortable with it.
There is a myth that side on causes injury but it is a myth, not true.
By horse stride he means that your run up in not smooth enough, and not natural (not how you would run normally).
Dennis Lillie approach helped me a lot with my run-up
'If you are struggling to find a regular rhythm, try this exercise:
to into an empty field with no obstacles nearby and from a marked point,
do a full run-up with your eyes closed. Imagine you are an old steam
engine looking to build momentum. Walk two or thre paces,
start to jog and gradually build up to about three quarter speed,
thinking of the sound and action of a steam train as you are running.
I have used this method many many times,
and it still works wonders in bringing out smoothness.'