In my humble opinion, the extra time and effort it takes to block a lace shawl, or scarf, is totally worth it. Below is a simple example and because they say, "A picture is worth a thousand words," I thought a picture would be worth it. :)
Before
While I was visiting my mom, I finished test knitting one of my patterns, using my handspun yarn, and was really excited that my concept had worked another time. ;) I threw the shawl over the chair, in my room, and took the picture with my cell phone. Then I packed it up in a plastic bag and brought it home.
At home, it was time to block it. Using towels, that I put on the floor, I pinned out the shawl. The difference is amazing. Laying on the back of the chair, you didn't really even notice that there was a scallop looking lace stitch used at the bottom of the shawl. You could see some holes, but not the design.
Blocking
I thought I would tell you the steps, that I use, to block my shawls and scarves.
1. Fill a basin with cold water. Soak garment until wet. If you used yarns that felt, be careful not to mistreat them by agitating them. You don't want it to felt. :)
2. Squeeze water out of the garment, without twisting or wringing the piece.
3. Roll in a large bath towel, or several towels layered. Either squeeze, or my favorite, place on a tile floor and step on it. Move your feet carefully along the roll of the towel. This will remove a lot of excess water.
4. Carefully unroll and using pins, that won't rust, pin garment out to shape it. Either use a blocking board, towels on a carpeted floor, plastic tablecloth or foam floor matts(the kind you can get for kids pay areas or work areas).
5. When dry, remove your pins and enjoy.
Step 3 is very beneficial! Removing the extra water into the towel(s) can save days of drying time.
If I am in a hurry, I have been known to turn fans on, pointing them at the garment to help dry the item more quickly. :)
Here is the back, after the pins have been removed. Compare this, with the first picture. :)
The front. Even though you can still see the scalloping, the points that I had pinned out, aren't as prominent. That is ok, because the knitting stitch didn't really come to points, I was just aiming at having that knitting stitch, which was used at the bottom of the shawl, scallop and that can still be seen.