In order to get the right fit, which is very tricky and specific with bras, it's really important we sew a muslin. You can use any scrap fabric of your choosing, so long as it is a similar weight as what your final garment will be sewn in. If you plan on using any stretch fabric in your finished bra, do the same with your muslin, or you won't get the same fit. I am using a stretch fabric for the centre back panel.
Cut out your pieces, and assemble as called for in the pattern. Remember to mark your darts! I always forget to do this...
Pin and mark any alterations. Mine fit pretty good, but needed to be taken in along the upper side seam. I suspect I added a little too much during my original pattern alteration!
If you are finding that the cups are too small, increase the curve of the upper and lower cup. If you are finding the cups are too large, decrease the curve of the upper and lower cups. Anna has demonstrated how to size down the cups Here. If you need to size up, do the opposite of what she does. It's really that easy. You can also play with the darts to alter the depth of the cup.
After sewing my muslin I decided to change mine from a side close bra to a back close bra. I did this by simply removing the "cut on fold" indication and adding 1/2" seam allowance along the center back seam. I also decided I would add a panel of stretch to the side front, under the cups. What changes are you making after sewing your muslin?