This article is pend with 30 round aluminum USGI AR-15/M-16/M-4 magazines in mind, but it can be made to work for most any magazine.
For a more professional look, check out magpul.com
Step 1: What you need
2. Paracord, aka 550 cord. 6"-6.5" per magazine
3. 100mph tape, duck tape works to, gaff doesn't hold up well.
4. A cutting tool. for paracord.
4. FIRE! lighter works just fine.