This is a picture of some handmade guitar picks (plectrums), posted by a member at MAKE.com. They are cut from gift
cards,  credit cards, hotel room keys, etc. Some are made from other materials like cardboard, "Handi Snacks" stick, CD, Toshiba laptop, and plastic
packaging.

Build Your Own Clone sells a good range of guitar DIY guitar effects pedal kits, which are great for the inexperienced maker. Each kit is based on a famous effects pedal and comes with absolutely everything you need to build the pedal. Step by step instructions should make assembly a breeze.

Effects pedals are a great introduction to the world of DIY guitar gear, because:

In Victorian times matchsticks were used as a sort of wooden Lego. Using small pieces as building blocks elaborate structures can be assembled, without the need for specialised woodworking tools. Using this technique Englishman Jack Hall make a guitar, mandolins, ukulele, banjo and other instruments out of matchsticks. The acoustic guitar, made in 1937, used 25,000 matchsticks.