Step 1: Gather a reliable time machine. We cannot stress this enough.
Step 2: Set the dials to the correct coordinates. Don't bother with decimal places, we're not here for precision.
Step 3: Find the cheese. It's usually hidden behind a velvet rope, but not always. Sometimes it's guarded by a fierce beast. Or both.
Time Traveler's Tips for Avoiding the Apocalypse will help you with the more...unusual cases.
Don't forget: the cheese is always moving. It's like that one friend who's always on the move. You never know where they'll be next week.
Happy questing!