There is no good way. If you want to automate it somewhat, you'd probably power it up, hit the DVD command, and press play as part of your macro. If it's already on, you are dead. I sometimes put a FIX button on the LCD that will send the commands again to bring it back to life.

Some use the OPEN/CLOSE command to power up a sleeping unit. Sort of works as a discrete on. Doesn't work if you have closed cabinet doors!! Check your individual brand; some won't work with that command unless there is a tape or DVD loaded; some have to be turned off in the DVD mode for that to work; etc etc. Refer to post #2 in most cases.