Not sure how old this is, but here are a few tips I've come across:

You can hit 'p' to shop when you're dead. This saves tons of time when you're alive.
You can hit 'o' to look at the last known update of all items (enemy and friendly), summoner names, kill stats, and other information. This helps when studying the enemy builds to modify your own.
You can rearrange items. This helps if you have keys that are harder to reach than others.

See you on the field~
ServantOfHelaman

Did not know how to /laugh, didn't even know you could. Neat.

Thank you!

op

Shift + 1,2,3,4 for different voices of your current champion

/ninja xxxxxxxx

saves xxxxxxxx to a text file where xxxxxxxx can be replaced by whatever you want

Is there a hotkey for buying the selected item? It would only save a couple of seconds, but every second counts for getting first blood.