There are 5 techniques you can do right now that will make mounting your horse 100x easier.
1. Only put your toe in the stirrup. Don’t get in the bad habit of sliding your foot all the way to the heel of your boot. This can also be dangerous if the horse spooks.
2. Stand in front of the horse’s shoulder instead of beside him. Grab your stirrup and turn it to face yourself and insert your toe.
3. Don’t grab the horn before you rise up. Instead, grab the far side of the saddle forks.
4. Keep your body against the horse the entire time. Try bending your left knee out to the left toe and allow your body to get in closer to your horse’s body.
5. Before you swing your right leg over, put most of your weight on your right arm (which should be resting on the right saddle fork) to easily allow your right leg to swing over.
Here’s a video to demonstrate how it’s done. Note that the cinch is not tightened the entire time: