Set up a spot in your house like this the first screenshot, where there are two two-tile objects sandwiching a little two-tile runway, then there are one-tile objects in front of the runway and in the upperleft corner. Lastly, there's a table in the upper right. Basically, you don't have to use those exact pieces of furniture, just make sure you have furniture in those places. Run up your little 'runway' until you get to the end. Immediately get out a Stringfish (or any other two-space fish) and drop it. This may take a couple of tries. If done correctly, your character should jump up onto the table.
Normally the fish would go where my NES games are, but since it can't, it puts it in the space in front of you. Since you are running, your character and the fish hit the ground at the same time. Now, since you can't touch the ground (due to the fish) the game forces you to stand on the next solid thing - the table.