wear a fanny pack with an extra pair of socks and change socks at mile 15? (j/k)
Seriously, my feet get fairly sweaty too, but I have never had problems with blisters wearing either 1) wrightsock double-layer socks or 2) the nike drymax? elite socks that Lybi got me for my birthday last year. The Nike socks are not double-layer, but are definitely moisture wicking and extremely light. Every other sock I have worn has given me problems - either too thick or wrong material.