A maxim is your subjective principle of action — what you are doing and why, stated as a policy. Build one clause by clause, choose the motive behind it, then run it through Kant’s three formulations. Each test catches a different failure, and knowing which one bites is the whole skill.
Build the maxim
1The situation
2What you will do
3Why you will do it
Your maxim
And the motive behind it
Run the categorical imperative
1 · Formula of Universal Law
2 · Formula of Humanity
3 · Kingdom of Ends
And the purpose you named
Is this command conditional?
Kant’s first move is to notice that most advice binds you only if you happen to want something. Compare the two forms of your own case.