One of the nicest things about putting your own chess set together is that there are no rules. After all, this is one of points in matching a set of chess pieces to the chess board by yourself, instead of looking for a chess set that has already been put together for yourself.
Still, there is a set of guidelines that can be followed to make this process fast and easy for you.
Match the size of the King to the board square:
The first thing that must be considered is the size of the base of the King. The King is the largest chess pieces and will therefore have the largest base diameter. The obvious goal is to make sure that the square of the chess board is larger than the base diameter of the Chess Pieces. It is fine to leave it at that. For those who want better refinement, the rule of thumb is to have a chess board square be 33% larger than the base diameter of the King. So, if your King has a diameter of 1.5 inches, then you should aim for a chess board with 2.0 inch squares (1.5 inches x 1.33 = 2.0). Of course you can select 1.75 inches and it will look great, but you probably don't want to go too much larger.