Cravings for Cheese Much?

This November has been a month a white sauces... and I never make white sauces.
Last week I made an attempt at cheese fondue, and it didn't turn out, so I made macaroni and cheese from the melted cheese/milk/butter mixture. Last night I made cheesy potatoes because the potatoes were sprouting and I needed to use them up. Both of them required a white sauce and both of the white sauces were kind of funky. The macaroni cheese sauce was grainy, and the potato cheese sauce wouldn't thicken!! Clearly I need to learn how to make white sauces!