What's the best way to improve crocheting speed?

Loosen your grip and relax your arms. Be careful not to prop your elbows or you could have tennis elbow in a couple of years.

Also lower your work, I've seen people hold it high and tight and that slows you down.

Clean dry hands with a little baby powder to absorb moisture or hand oils and a really good light.

The best way is to just keep on crocheting. The speed will come naturally. If you try to go faster, you almost always end up making mistakes, which takes more time in the long run. I've noticed that patterns that I've done more than once in the past which took me a long time, now go much faster. I think it's mostly the "muscle memory" and the rhythm of it that increases speed.

The real way of learning is by practicing... a lot! To achieve this, try these very simple exercices. 1) Position your hands correctly. Your left index should be on the 'F' and your right one on the 'J'. 2) Now, try one row at a time: QQQQQ, WWWWW, EEEEE, and so on, WITHOUT looking at your hands. You should have a 'piano technique', meaning that you must use the right finger for the right key, not always your index... 3) Then, try the alphabet, and once again, without looking at your fingers or at the keyboard. Sure, it will be hard at first, but you MUST learn the positions of the keys by heart if you want to achieve fast typing. The hardest parts are the numbers, basically because they're 2 rows above your fingers. So it will take practice, but trust me, it will be worth it! Good luck!

Tension is a big factor like a lot of people said. One thing I noticed that improved my speed considerably was to crochet around people faster then I was. I found myself unconsciously trying to keep pace with them. Once I realized how fast I was going it was a lot easier to crochet faster alone. Maybe my hands just needed to find out on their own that they actually could go that fast?

I find that when I have the perfect "tension" on the yarn is when I can crochet the fastest. Find a method of holding the yarn that is the most comfortable for you and allows the right tension....and.... this is going to sound silly, but... rub your hands lightly with a little baby powder from time to time, especially if you're using a synthetic yarn which can make your hands get a bit sweaty and "catch" on the yarn which slows you down.

I crochet, I used to be really slow but then I practiced and now I can make 2 scarfs a day!

Practice. I don't crochet, but I do knit and just by knitting different things and using different stiches, I have become faster.

Practice Practice Practice until it is second nature.