A few things I have learned over the years. It is very important to have a strong, well hidden knot. When tying the starting end, make a small knot that will pull to the underside of your fabric and go into the fabric on the quilting line about 1/2 in front of where you are headed, and quilt over the knot. When ending, point the needle back toward where you just stitched, under the top fabric about an inch, and then, without pulling the needle out of the fabric, point the eye end back to where you stopped stitching and on the other side of the line of stitches, making a u-turn inside the sandwich, pull tight and clip the thread. The end will go back under. Long and complicated sounding, but your knots won't ever come loose.
The other thing is this. Try to keep your stitch size even. Worry about how big they are later. Smaller stitches will come with experience, but consistency looks good, no matter the size of the stitch.
Have fun. Hand quilting is my favorite part of quilting. I really enjoy studying how the colors on the different patches interact with each other.
Didn't mean to write a book. :roll: