
Hi! Welcome to the Forum! You've made a great choice of breed - the WFTs I've met have been great little dogs, full of energy and go, yet not too large - proper dogs!
When you got to see a litter, take your time. Don't be rushed. First, make sure you meet the mum, and see that she's friendly with you. If she's nervous or snappy, walk away - don't even look at the pups, because they may well have inherited her dodgy temperament.
Make sure they're all sweet-smelling (though they may have pooy feet etc, they shouldn't have a 'sour' smell to them. Their coats should feel 'healthy' (hard to describe) with supple skin and no sign of scurf. Their eyes should be bright and clear, and their ears clean. Check for hernias etc.
Assuming all is well on that score, sit on the floor with the puppies and let them climb all over you and play with you. Study them all, picking them up, stroking them, playing with their toys, handling them as much as possible. Watch how they interact with you and with each other. Soon you'll find yourself being drawn to particular pups, and these are the ones to take your choice from.
Oh, and once you've chosen one, definitely leave a blanket or old jumper or something with them in their bed, for when you collect him. It makes their first nights very much easier for them.
Good luck!