How can I skip every other column when dragging a formula across cells in a row?

I am trying to drag a formula across a series of cells in a row so that I don't have to manually enter it each time. The problem I'm having is the data that I'm referencing is every other column on the referring sheet. The dragging option wants to pick up each column, when I want it to figure out it's every other? Can someone help me with this please?