Before my first solo, the instructor repeatedly had me go through the emergency procedures. The scenario he most stressed was an engine failure on takeoff. At least if it all goes quiet at pattern altitude, you've a little time to assess your options.
As for the flight, it didn't take long for me to embarass myself. I bade farewell to my instructor, then tried repeatedly to start the engine - having overlooked 'Mixture - FULL RICH' in the checklist... After that, it was easy!
Incidentally, how many pilots had a (slight) hangover when they made their first solo? This seems an oddly common combination...