Best advice I ever got: "Go make mistakes! Because you learn more from your mistakes than any lessons I could give you." Second tidbit from the same lady: "At first, buy fabric cheap enough you won't be afraid to make mistakes on it!"
I am into quilting, but also do alot of other projects - purses, wallets, lunch bags, potato bags, aprons, ...
My suggestion is to pin it before you sew it, because fabric stretches. Even in quilting, if you pin the pieces where they are supposed to meet, then you can ease the rest of the fabric and avoid wrinkles in the seams or pieces that hang out beyond where they are supposed to be.
My mom started me on embroidery to perfect my stitch length and tension. As a former bridal seamstress those were the best learning experiences for hand sewing.