Here is a design for an inexpensive and easy to make portable solar water distiller.
It works by allowing evaporated water to collect in a reservoir created by the space between two concentric plastic bottles.
The reservoir is another plastic bottle covered in a black colored fabric to make it hotter than the surrounding structure.
The collector is kept at a lower temperature using evaporative cooling.
The temperature differential created by the evaporated cooling should allow the condensation process to happen a little faster than it would without it.
Step 1: Materials
a hot knife for cutting plastic
a vapour mask to avoid fumes
one or more white socks
one or more black socks