Why is 'to' sometimes dropped in these kinds of sentences?
What you want to do is make a plan
There's no 'to' between 'is' and 'make'.
The next thing you want to do is to stay in the present moment.
There is 'to' between 'is' and 'stay'.
The first thing you need to do is to trim vegetables.
The first thing you need to do is trim vegetables