I got tired of my bike's pedals catching my laces, so I decided to ditch my laces and go for something else. I ended up with using inner tubes to turn them into slip-ons. They stretch out to put your foot in, and stretch back tight. Mine are incredibly comfortable and very convenient.
All you need is a pair of shoes (laced), an inner tube, and scissors. Go to your local bike shop and ask for old inner tubes. Explain why you need them and they will most likely always give them to you.
Step 1: Unlace shoes
A very easy part. Take off the shoes' old laces. Keep them around to get a sense of how long the new ones need to be.