This is a step by step instructional on how to make a simple yeast starter.
First you want to start off with about a half a cup of DME some sort of vessel in which to house the starter, yeast(not pictured), and some sort of cover. Sanitized aluminum foil wrapped over is fine.
For this starter we’re going to use 1500ml which equated to about 1.030 OG. For the proper pitching rates for your starter i suggest using.
Here is our tube of White Labs WLP002 English Ale Yeast. As you can see the date on the vile is April 24, 2011. White Labs post dates their viles 4 months, so this yeast was only 2 weeks old when i used it.
I use a homemade stir plate, which is not necessary but its a great cheap way to increase yeast population. Now you let your starter sit until it has finished primary fermentation(or you can pitch at the height of fermentation, your choice). After it has finished, you want to stick the starter in the fridge for a day or so, so that the yeast will drop out of suspension. You can then wait until brew day, pour off the majority of the liquid and let it warm up. This will create a slurry that you can pitch into your beer.