How can I airplay to my Apple TV without having to turn it on with the remote first? I can stream / airplay fine from my macbook or iPhone to my Apple TV, however whenever my Apple TV is on standby (the light is off) I have to manually switch it on with the remote control first, and then choose to airplay to the device.

I was always under the assumption that trying to stream to it would wake the Apple TV up from standby. Is there a setting I have missed? It didn't used to do this in previous years to my knowledge.

How can I stream to my Apple TV without having to manually turn it on with the silver remote first?
The short answer is, that you are doing the right thing, the Apple TV should just wake up when it gets an AirPlay stream coming at it.

My Apple TV (720p) one is having similar issues, you have to wake it up to stream to it, and it has other issues.. I would suggest a factory restore which is what I am going to do.

It will loose all your preferences, but should fix the issue. Worst case you could also look at reinstalling the firmware using a Micro USB cable and iTunes on your PC or Mac.

Instructions on Apple.com for both methods