I recently discovered a pretty nifty trick when developing Google Chrome. If you have your cursor inside a style attribute which is a number while in the Chrome Developer Tools, you can change the value using either the up and down arrow keys, or using the mouse scroll wheel.
Many may already know about this, but finding this is going to be a huge time saver for me. I can't tell you how many times I've been fine-tuning a position or layout only to have to retype the value hundreds of times to test them out.
Check it out below