you just need more practice. I don't use a thimble either.
You want to make sure you have a good needle for hand quilting. I like the #9 (it's easy to thread the needle), but the #10 needle sews better. Fox glove makes a good hand quilting needle, but I've heard good things about Roxanne's.

Have a look at the tutorial by Andrea "borntohandquilt" on the board. I gave up trying to get multiple stitches on the needle and now do the stab method with much pleasure. Most quilters say that the evenness of the stitch length is more important that the actual length of each stitch.

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.

I have always been told that it is not the length of the stitches, but the fact that all are consistant. Looks good for first try. Keep up the practice, and stitches will get smaller. Nice bright colors.

it takes loads of practice and you can always call it Big Stitch quilting.

Nice quilt... are you finding it hard to go through the fabrics?

No, not really. I just find it hard to keep them consistent.

I bought a thimble from Walmart, but it's quite cheap. It was only $1.39. I figured a good one should cost more. How do I buy them online? How do you know whether it'll fit? What's the average cost of a good quality thimble?

I also bought off white quilting thread. I can't do thread that matches each of the different colored fabric. I'd have a bunch of them and Walmart only sells the basic colors.

My final purchase today was 1/4" Quilter Tape. I'll try that, see if it helps me get more consistent stitches.

Good suggestions. Keep em' coming. :)

There is a sticky tape you can get at the quilt shops. You lay it beside the seam, it gives the quarter inch away and there are marks like on a ruler to guage the stitches by. They could be close or as afar apart as you want.
I admire you, keep on keeping...

Hang in there and keep practicing. Sometimes it helps to have a practice sandwich on the go. Do a line on your practice bit, before picking up your quilt. Eventually you will find a style/method which suits you. I don't think it's the money spent on the thimble....I have some very cheap/second hand ones that work really well. My husband once spent around $20.00 on a beautiful Japanese metal/leather thimble...bliss to use, but I left it on the coffee table and his dog (then a pup) ate it (no ill effect to the dog....but I still mourn it:)).

Keep going! :D

Once I got the "rocking" feeling down, mine looked much better. I don't know when I'll get back to hand quilting though...it takes a TON of time for me!