If you are cutting thinner stock, such as 3/4" or so, cut the 1st piece 1/4" or so longer than needed. Place it on top of the next piece and make sure the left ends are exactly even (assuming the stock is to the left of the blade). Clamp if necessary. Now make your cut through both pieces. They will be exactly the same length.
If cutting multiples, use one for a pattern, place it on top of the next piece to be cut, then make the left ends even. Now slide the stack up to the blade so the pattern just touches the blade, and cut the lower one.
Alexis de Tocqueville was a very smart man.