jo definitely write everything down, I also started writing times and things too to see where I was having difficulties. My downfalls is the evening where I'm tired, I make sure I have lots of low syn or free snacks in the cupboard to pick at. Today I'm studying so like to pick, I've made a plate of bits to pick at rather than a proper lunch.
Also make sure the plan is doable - don't plan a new meal on a day which is busy, I know tuesdays and Fridays I'm shattered so those days are easy meals either frozen from another day or something like stir fry/pasta where there's minimal prep, this is so I don't get stressed and think Fuck it and raid the cupboard for snacks!!