You've gotten great advice so far. Keep practicing...it will get easier and more consistent. I agree with marking your stitching lines with a pencil. I've never had pencil marks not wash out. This will guide you as you go for consistency in your stitches. I personally find marking with tape more difficult. I think it 'stiffens' the quilt too much for me. But try either method and see what works for YOU. We all function differently. And try some different brands of the same size needles. Some just work better than others. I really like Roxanne's but they can be difficult to find locally. I always have to order mine online. Thimble or not is your choice. I like the Thimblelady thimbles. Nice deep dimples to help control the needle and a really good fit following their measuring guidelines. And, for the moment, I'd use a thread color the same as your fabric. Less noticable until you feel comfortable with your stitching.