EDIT 2014-7-24: With the release of Crius, literally nothing in these posts can be used any more. Do not try to use them as a guide. It will not work.
EDIT 2016-03-20: New guide here.
At least two blogs have posted capital building guides, but they both use the word 'copy' at some point. Here we're going to do it right.
EDIT 2013-6-8: I now have some minimal guidance for building from copies. If you want to start production with less than 24 billion, please see this post.
This guide will be split into several parts covering different topics:
1. Introduction (you are here)
2. Ship blueprints
3. Component blueprints
4. Researching your blueprints
5. Moving capital blueprints safely
7. Location, location, location
8. Moving minerals
9. Actually building stuff, finally
10. Selling your ships
About this guide:
This guide does not comprehensively cover every single thought that there is to have about capital manufacturing. A reader who wants to use it is expected to be able to use problem solving, to evaluate whether or not a process will work for them, and to run the numbers themselves instead of believing what they hear on the internet. Basic spreadsheet skills are also likely to be useful.
It will cover exclusively the building of jump-capable tech 1 capital ships (carriers, dreadnaughts, and rorquals), from original blueprints, in lowsec, for profit. Many of the tools it provides could be useful for building from copies, for building freighters and orcas, or for building in wormholes or nullsec, but these things will not be covered.
The guide's posts are arranged in the approximate order you want to think about the various topics when setting up capital production.
Also, it's going to be extremely boring. I know blogging ~best practice~ is to throw in pictures whenever possible, but I'm going to ignore that and go with a wall of text interspersed with spreadsheets.
The short version:
There is a nontrivial amount of money to be made building capital ships. Also, once you get it up and running, it requires very little time investment to keep going. As a highly profitable, low effort, non-grind-type profession which also doesn't require you to adjust market orders by 0.01 isk, it is literally the best thing in eve.
You can expect margins of 25-35% over mineral price. How much you make per month depends on how many manufacturing slots you are able to run; at the time of writing I have 30 slots and make 3-7 billion per month, though I often have a number of slots going empty because of a component bottleneck.
One of the reasons that capital manufacturing is so profitable is that it has high barriers to entry. Big ones include knowledge (most people have not run the numbers; and most people think that building a capital ship is a big, difficult task), isk (capital blueprints are expensive), and risk aversity (zomg moving expensive things through lowsec).
It takes a while to start up a capital manufacturing process, so you don't actually have to meet all the following requirements before you start looking for blueprints (more on this in part 2), but some minimum requirements and some recommendations are below:
Capital ship construction 3 (4 for rorquals)
One building character
24-ish billion isk
As many building characters as you can fit on your account/s
Jump freighter and cyno alt (preferred) or cov ops transport plus mineral compression ability
Personal corporation so that your alts can work together via a corp hangar
Blockade runner tengu (see part 5)
Scrapmetal processing (if using mineral compression)
Advanced mass production 4 (10 manufacturing slots)
Advanced laboratory operation 4 (10 research slots)
Metallurgy 4 (20% faster ME research)
Accounting skills (to reduce tax)
Go to part 2: Ship blueprints