The thinner you make your strips, the larger the final loop will be.
Look at the folded edge of the paper between your two original end slits. Get Out
If you find the paper keeps tearing, try using a slightly thicker dense paper for more durability. The thinner you make your strips, the larger
Find the folded edge. Cut a slit about 1 inch from the left side, starting from the fold and stopping about half an inch before the open edge. Do the exact same thing on the far right side. The thinner you make your strips
Between those two end slits, cut more lines alternating their starting point: Cut almost to the open edge. From the open edge: Cut almost to the folded edge.