Brother Lawrence said to arrive at such resignation as God requires, we should carefully watch over all the passions that mingle in spiritual as well as temporal things. God would give light concerning those passions to those who truly desire to serve Him.
It can be incredibly hard to sort God's will from our own desires at times. In fact, I've sometimes found that the only way I could work it out was to work out what I felt led to do
but didn't really want to do - that was generally what God eanted from me! But that's not a fantastic test, especially if we're haunted by ideas of what we
should be doing, or being.
Brother Lawrence's advice needs to be taken in the context of his overall theme - continuous conversation with God. Let him lead in little ways, and the big things will grow from there. Noticing the lonely-looking person over there, and feel a tug towards them? That's probably God. Remembering an acquaintance with financial issues? That might well be God pointing you toward doing something for them. Don't worry so much about achieving the big stuff... preaching up a storm, being renowned for your work amongst a minority group, whatever. That sort of thing typically happens while someone is focused on obeying God every minute. And it happens because God orchestrates it, not because his servant does.
Naomi