The perfect tip before you get rage of halone:

Build hate to lose it.

If you lost hate on a mob AFTER you flash and landed a savage on it. Chances are the hate is already solid to begin with and it's not ganna increase for you. Start building it on another mob instead. Also savage blade deals more enmity than flash, if you only have two enemies, you alternate savages between them rather than flashing them to death.

Fight or flight is probably your only tool for regaining hate. After that it's up to the DPS whether they want to stop or not... though if you can hold out well, usually they can tank the rest on their own by the time you lose the hate.

Also shield bash your enemy at 5-7% health, let DPS finish off the last mob, while mobilizing to find the next pack immediately (exception is if it's a large link, in which you should wait for healer). This way, you can build an earlier hate lead, unless your DPS are dicks and wanted YOU to finish them off... which is very aggravating and stupid (no you shouldn't be expecting mercy stroke from a GLA/MRD that's not even in the 20s yet... genius).