Catching fish on your own homemade bait is very rewarding, but don't expect the humble boilie to be any sort of miracle bait.
When US carp anglers, including myself, first try boilies, they expect them to be an instant bait. Sometimes boilies do work right off the bat, but in most cases it helps to introduce freebies (free bait, or chum, is an important part of 'Euro style' carp fishing) into the area you intend on fishing over a week or two. The problem with this in relation to boilies is that it either requires you to make or purchase several pounds, which some may find time consuming or expensive.
As zaqxsw states, boilies are merely a mix of flours, eggs, flavor, sweetener, and bit of oil smooth the rolling process. In this regard they are nothing more than pasta, and really aren't much different from a doughbait, except for using eggs instead of water and being boiled to produce a tougher skinned bait. The main benefit of this style bait is that it lasts a long time and won't be picked on by crayfish and small fish (like bluegill, shad, minnows, etc) as easily as a doughbait. Because of this you can confidently heave a rig out at long range without worrying about the bait flying off or slowing dissolving. The downside is that some of the attractiveness will be boiled out of the bait, and it doesn't disperse its scent as readily as a doughbait.
I'll try to make some boilies tonight and document the process. I fish for carp almost exclusively, but I haven't made boilies in years, if that tells you anything. Boilies make good hookbaits, but I don't usually fish them alone.
Fishforcarp.com has pretty extensive details on making boilies, but they are geared towards an English audience.
I created a
tutorial on tying hair rigs on this forum.