A Rail Fence block is a good one--three strips, all the same length and width, sewn together. These are alternated, so that the quilt develops a woven appearance, with the blocks going from horizontal to vertical to horizontal to vertical all across the row.
You can sew long strips of fabric together and then cut them down to the smaller sizes of the blocks to save time. To determine the size of your block, figure out what size strips you want to use. Sew three of them together, measure that unit, and cut the blocks to that length--you want the block to be a square. Any size square will do.