To avoid skipped stitches when sewing velcro I use a very small stitch length around 1.5
If you are skipping stitches when putting on binding, are you getting the skipped stitches when going over seams? If so, then the seams are too thick or your needle is too small.
Clean the bobbin area. Also, clean the bobbin casing you may have a bit of lint caught in the tension spring. Put a small drop of oil on your finger and rub the outside of the bobbin case.
Clean the needle tensioner as well. Also, be sure you are threading your machine with the presser foot UP. To clean my tension disks I get a long piece of dental TAPE, unwaxed, tie knots along the length and run this through the disks.
Hope this helps and keep us posted on your progress.