My boots eat laces, and I know I'm not the only one. Paracord is a great replacement, but it has a big weakness. This video shows you how to correct that weakness, as well as teaching a handy repair technique.
The heat gun I use can be found here, and the appropriate heat shrink tubing is here. It can be bought in a variety of colors and diameters, so pick whatever fits your project; I find that 3/16" is perfect for paracord.