I have only done this about twice because I get scared ****less...
Don't laugh - but do breathe quietly before you say anything. And then - trust yourself.
If this is sort of a first - I'd stick to three carders anyway, for now - past - present future is popular, though I'm not big on predictive; I am more fond of yes if - no if - maybe if (thanks, James Ricklef !) Loads of cards would make you (well, me...!) feel panicky if you have any problems all of a sudden.
Don't be afraid to ask the sitter if what you just said suggests anything to them, either. It can lead you onward.
And - if you get stuck, never be afraid to say so. But - relax, and it will come to you. If it doesn't - there are experienced professionals who have said to sitters: "I am not getting anything.... I need to leave this for a while" - look at the pro threads here !
Have fun. Tarot is not a courtroom