Skill

A student mentioned to Sifu that he wasn't to confident with his shuai jiao & chin na applications.
He knew the drill but couldn't pull it off effectively or consistently.
http://neijiaquan.co.uk/shuai_jiao__chin_na_application.htm

I have experienced this myself and can tell you that the only solution is 'practice'.
Nothing replaces practice.
Once you've done the same drill hundreds of times it becomes second nature and your skill increases significantly.
You learn better timing, positioning and leverage.

For example: At home Sifu drills the shuai jiao & chin na applications solo in order to improve memory and spatial awareness.
10 per day for 7 days.
He also partners them weekly with me.
This combines 2 effective methods for gaining familiarity: solo & partnered.

Be patient with yourself - the skills will come.
You just need to put in the practice.