Whe I wrote my reflective accounts, I wrote about what I did and matched it up to the performance criteria I was trying to achieve.
You will also need to reflect on the activity you carried out and write about what went well (eg you got lots of information about a particular child), what did not go quite so well (eg the child began to notice you were observing them and started to behave differently), how you could improve your practice (eg by using a different type of observation) and what you would do differently next time (eg not make the observation quite so obvious).
Hope this helps and well done for getting this far!......