What I do is make sure that i cut out accurately and sew accurately as I make the blocks (which is prior to where you are now, so that isn't really helpful now, but for the next time.) I also PRESS w/ starch as i go. Pressing is just lifting your iron up and down so not to stretch your blocks and make them wonky.
For where you are, press the block using more of an up & down motion. IF you have to trim, make sure to account for your 1/4" seam.