A frequent beginner mistake is to hoop too tightly. There should be about 4" of "give" in the quilt after you have hooped -- meaning you should be able to move the quilt 2" or so up and 2" or so down. It should *never* be drum tight. You are probably finding it easier to quilt without a hoop because you are able to move the fabric now. I have tried hand quilting both ways, and have much better stitch quality when I use a hoop -- but hoop very loosely.
What size needle are you using? Smaller stitches come with practice. If I were you, I would create a practice sandwich before tackling an actual quilt.
Aim first for making even stitches, all the same length. Once you are pretty good at that, you can start trying to make your stitches smaller. It is more important to have even stitches than small stitches.