watched your video, nice shooting.
whenever i go to the range to actually train and not just mess around, i always focus on my stance, grip, and trigger control. this is not in order of importance (as they are all important), but in chronological order. i have the pistol and magazine sitting on the table in front of me, when i go to start i try to "set" my feet into a comfortable weaver stance. i try to replicate the same stance everytime. next comes grip, i notices that you have your index finger in front of the trigger guard. in my experience shooting like this leads to a horizontal pull and overall discomfort. i pick up the pistol, with no magazine, and open my right hand all the way seating the web between my thumb and index finger into the backstrap of the pistol, then and only then do i try getting my left hand situated. i generally place the tips of my left hand fingers in between or just in front of my right hand knuckles. if it feels at all wrong just put it back on the table and restart. then while im shooting i am always thinking about controlling my trigger pull.
of course there are other core parts of technique to work on, but i have found that these three are the most important for me to focus on.