To keep the LEDs in place, I used a small scrape of plywood that fit tightly inside the housing. Position the LEDs as close as possible to each other to make the light more concentrated. Wrap the block in electrical tape to hold the LEDs in tightly.
To make everything fit inside the housing better, cut the wires of the LEDs to about half their size and strip the wires longer (Only if you bought them from the link). Solder all the positives together, and all the negatives together. Zip tie the wires together.
For a small, sturdy housing, a used the tube from ceramic wrap. Cut the tube to about half its size. I used a switch from an old computer tower, nice and square shaped. In the back of the housing, trace out the switch and cut out a hole for it.