[Freeswitch-users] Suggestions for creating diff's in git...

I've been using SVN for a couple of years, but I'm quite new to git (as new as the FS project). I haven't yet found a good (easy) way to create diff's, to send up to jira cases, does anyone have a good tutorial for this? I've made some patches, but I haven't submitted them yet because of this. Regards, Peter