One solution is to use a simple support block, see photo. The nice thing about this block is that it allows you to pivot the workpiece as you push it through the saw to “follow” the direction the blade is wandering.
The guide is nothing more than a block of wood that has been beveled on one end to create a “V” point, see Fig. 1. On the other end, the top of the block is cut away to make it easier to clamp it to the table of the band saw.
To use the block, simply clamp it to the table so it’s just slightly in front of the blade, see Fig. 2.