Step away from it for a while - some days we are our own worst critic. Another day you might look at it and wonder what was so bad.
Maybe get some scrap materials and make some samples of quilts you would like to make in the future. Remember these are "idea" blocks and do not need to be perfect.
Practice! I don't know of anybody who does anything well without it. (If you know of someone please let me know so I can shake their hand!)
Have fun!!!!!! Make a mistake in every quilt and see if anybody notices. (kind of like I spy or where's Waldo thing)
Don't give up! Making a perfect quilt is NOT life or death.