Doctor Martens shoes (manufactured in U.K.) come only in full sizes.
I have that problem. My solution is to look at the form of the shoe. If it is a wide shoe, I buy my size(or sometimes smaller). If it is too narrow(boots, tight sandals, high-heels), I buy a size larger.
And would you believe that there is no standard as to how big a shoe is? I have great fitting shoes varying from an 8½ to 10, but they all fit great.