Nobody likes the idea of practice! Trust me, as a teacher, I know this! Even I don't like to take the time to practice, although I know it is the best thing for me!
In quilting, as in everything else, we want to use the time we have carved out of our busy schedules to get right into a project, not spend the precious minutes on practice and skill building.
Well, I am here to try to convince you that any time you spend on practice will pay off big in better blocks, better quilting, better quilts!
If you are a beginner, one of the most important things you can work on is sewing a straight seam. You can learn a lot about how fabric behaves and how your sewing machine stitches when simply sewing straight seams, no matter what the width. Cut some fabric (that you don't care about!) into selvage to selvage strips, about 2" to 2 1/2" wide. Place two strips on top of each other, aligning one long edge and sew along that edge. Concentrate on sewing a consistent width the whole distance. Don't let the strip waiver or wiggle. Keep doing this over and over, until you get happy results.
Practice pressing techniques by pressing those strips neatly. Remember, pressing in not ironing! You don't move the iron around a lot when pressing. Use an up and down motion, press from the right side of the fabric, using a hot, dry iron.
Make practice blocks before cutting into important fabric. Make sure the block goes together well and measures the correct size.
Set up a quilt sandwich to practice machine quilting. Getting the sandwich well done is half the battle, but once you have it, use it to quilt until it is covered with stitches, then make another one!
Rotary cutting is another area where I think many quilters need practice. Cut up some old fabric, practicing straight cuts with even pressure on the cutter as you go across the cut. Practice safety while cutting, always!
Choosing fabric for a quilt takes practice, too. Ask a friend to share this practice. Go to her house and use her stash to choose fabric for a "fake" quilt. Pick a design that uses more than just a couple of fabrics, and just play until you have a group that you would be happy using in a real quilt. Invite her to come to your stash, too! (Using another's stash lets you play without any preconceived notions of what goes together.)
Practice may not make perfect right away, but it's good for you!