As a low-time pilot I don't have much to say of course, still here goes for what it's worth: the first solo is indeed a moment of stress, if only for the long time it has been coveted. To keep the stress to a minimum, I think the instructor should best make the first solo resemble as much as possible to what the student is used to. Whatever that may be. For myself I was used to doing touch and go's, and lots of them. So when the moment was come, my instructor told me to go off and do two or three circuits - he didn't even mention the T&G's, that was an evidence.
Upon reading this thread, I realised I was sent off solo without ever having trained anything like in-flight power failure - a bit uncomfortable that thought, looking back now.