Getting ready the other day, I killed two birds with one stone (ooh, is that politically correct to say?) and put together a quick pictorial 'how-to' tie a bow tie.
Step 1. Begin by wrapping bow tie around neck, leaving RIGHT end a little longer
Step 2. Cross the longer RIGHT end over the LEFT end
Step 3. Take the RIGHT end (now near your left shoulder) up under LEFT side and pull both ends tight
Step 4. Take the LEFT end (hanging straight down) and fold like this (with folded edge facing out towards your LEFT side)
Step 5. Take the RIGHT end from off your shoulder and drape down the middle of first fold made with LEFT end
Step 6. Fold RIGHT end (now draped down middle) up, under & behind the first fold made with LEFT end - and push the RIGHT end through the natural loop behind the bow itself (pushing the fold of the 2nd half of the bow towards your RIGHT shoulder, so that the 'end' remains facing outward, towards your LEFT shoulder)
Step 7. Grab the folded end of the front bow with your left hand, and the folded end of the back bow with your right hand; pull both ends at the same time to tighten, then adjust as necessary.
A version of what should be a slightly imperfect finished product.