As a beginner, I avoided this kind of increase for a long time because I couldn't do it properly. I had no teacher and no videos to view.
First of all, I knew I was supposed to knit first through the front of the stitch but stop short of slipping it off the needle...I was afraid to do anything! I tried to knit into the back without even pulling the working yarn through to knit through the front! Then I had a hard time figuring out exactly where to bring the right needle through after knitting through the back, when it finally was time to slip things off the left needle; I kept trying to bring it all the way to the front of the left needle, under the knit stitch created when I knitted through the front loop. What a mess! It took a lot of trial and error, because I had no instruction or visual cues.