There are a few ways to start a siphon. At the very least, you will need a racking cane (preferably curved) and at least three feet of siphon tubing.

There are a couple methods for using a racking cane to siphon:

1. You can place your racking tube into the fermenter and attach your siphon tubing to it. Place the fermenter at a level that is higher than your carboy or bottling bucket. Then, simply suck on the end of the hose until your siphon begins. Some homebrewers suggest filling your mouth with a shot of vodka before doing the sucking, you know, to sanitize your mouth, right? I think this is just an excuse to drink a shot of vodka, but I guess that's not necessarily a bad thing.
2. Take your siphon hose and attach it to your racking cane. Then, run water through it, placing your finger on the end of the siphon hose once it is full. Then carefully place the racking cane into the fermenter, keeping your finger on the end of the hose. Then drop the end of the hose into your carboy or bottling bucket, and, voila! Your siphon should start. This method may take a couple of tries, but once you get it down, it's very easy.
3. If you are transferring from a carboy, starting a siphon is made very easy with the help of a carboy cap. You slide your racking cane (curved and first) into the big hole, place the racking cane gently into the carboy, then slide the carboy cap down until it seals on the glass. Attach your siphon tubing to the racking cane and place the other end of the tube into your bottling bucket or keg. Now, just blow into the hole on top of the carboy cap, and your siphon will start.

The Fermenter's Favorites Rack Magic Autosiphon is an alternative to the standard racking cane and is wonderful tool that makes starting a siphon effortless. To use the Rack Magic Autosiphon, gently pump it until liquid starts to transfer on its own. This should occur within a handful of strokes. It's that easy.