I started by just doing a quilt of 5" squares, my first is much treasured and very pretty.
Something like this
www.diaryofaquilter.com/2014/09/fast-four-patch-quilt-tutorial.html
But just 5" squares, once I'd finished quilting in the ditch, I went diagonally through the squares to give it a bit more of a quilty look.
It's a great way to practise all the techniques and if you go slowly then your get very good results :) it's a good way of practising sewing in the ditch and getting a feel for how it all comes together, the ones that involve pieces if you have never done it before may be tricky, but if your brave and have cut out the pieces already then I would just go for it! I'd love to see a picture but understand it can be daunting :)
Seem allowances being perfect and pressing not ironing all the seem allowances is very very important, i hate that bit but it does give the best result
When you come to sandwiching it, I'd suggest getting some temporary fabric spray :) pinning is a nightmare, where as spray sticks it all together, it doesn't shift and it washes out on the first wash. Always lay flat, and roll from the top to the middle, them spray and flatten in pieces for the best result.
I wish you so much luck! I've not done any for a while have become obsessed with crocheting animals recently :)
If you have any questions I'm happy to help :)