Here is a great almost invisible method to increase by knitting a new stitch in the loop from the stitch on previous row. You can do it after or before a stitch just as we show in the video.
Right side: put your left needle through stitch 2 rows below the stitch on the right needle. Lift it up on your left needle and knit it in the back loop.
Left side: put your right needle into the stitch under the first stitch on your left needle. Pick up the loop and put it on your left needle. Knit this new stitch in the front loop, and also knit following stitch separate as usual.
This is also a great method when you need to inc two stitches right next to each other, without having to work a stitch between them.
You can knit 1, make a inc in the st below, then make an inc in the st below next st, then knit that st.