If you could learn a technique that would even-out your knitting stitches, would you want to learn it? If you found that there was a way to make the edges on your crocheted afghan lay flat, would you do it? If the squares that you got back from your weaving group were all different sizes, and they weren't supposed to be, would you know how to fix them?
I'm asking these questions because many fiber hobbyists don't seem to know what the one answer is for all of these problems. Blocking!
Blocking is the final shaping of your finished or nearly finished garment, afghan, purse, etc. It fixes all the little "oops" problems, straightens edges, gives you the right size, and evens your stitches. It definitely makes your item look finished and professional.
Last week, I was a judge at the county fair, and only one crocheted afghan had been blocked - it was wool, so presumably the stitcher knew that it should be blocked, and the finishing showed. I gave the afghan a first place ribbon.
The other 35 crocheted afghans that I looked at had curled corners, or unstraight edges, or bubbles and uneven stitches. If the stitchers who worked so hard on their afghans had taken just one more step - and blocked their afghans, none of these distracting results would have remained.
It doesn't take much time to block your item, except drying time.
For lightweight items, you can spray with water, then shape to the desired size. For heavier items, like afghans, submerge in water to get completely wet, roll in several towels to blot excess water, and shape onto a flat surface like a bed, couch, or dry towel covered floor.
In both cases, hold the desired shape with pins that won't rust (alot of people use flower pins for this) and let dry flat. Depending upon the weather and temperature, this could take awhile - a day or two.
Here's a crocheted baby vest that my daughter just made - her first! She used rust proof pins to block the sweater to shape, then let it dry on her ironing board - for a day.
For small items, you can steam with an iron on your ironing board, making sure to hold the iron ABOVE the item, not on the item. You definitely don't want to flatten your stitches. Again, pin and let dry completely - just because it's not hot, doesn't mean it's dry.
Don't hang or drape the item! That will stretch it out of shape.
There are a lot of great videos online that talk about blocking. Here's a simple set of knit blocking instructions that I think are good: Blocking tutorial.
Whether you are knitting, crocheting, weaving or embroidering, you really should consider blocking as your final step. Without it, your item is just not complete!