InsaneJournal

Fed up of logging in and out as different characters? If you're on firefox, you can use lj login to switch accounts at the click of a button.

When downloading icons, you can use this firefox add-on to download all the pictures on the page at once (then you can delete the ones you don't want).

If you make your own icons or use images for other things, you can upload them straight to photobucket etc. with one of these add-ons.

To upload the icons again, you can download one of the icon uploaders linked from here to help you.

Actually, that post's pretty good for other useful things to, most notably the thread unfolder for if you hate it when threads collapse.

If you have other useful tips, do please let me know!