I agree. In a general guideline, start small and work your way up. Also, do not wait for self-imposed ideal opportunities. If you do not have a boat, go sailing with others as much as possible, whether for an hour or a day, get some experience then maybe volunteer for an offshore delivery trip. Do not say to yourself, I want to sail offshore so I will only look for those opportunities, go sailing as much as possible, and when on the boat ask the captain if you can helm, trim sails, and not just be ballast.
Go to local yacht clubs or marinas and post your name to crew for weekly races - even if you are not interested in racing the experience will be valuable and teach you about sail trim, etc.
Also, I learned a lot once I boat a bought, being captain is very different than being crew. If you want to buy a boat, do not delay for the next 10 years to buy 'that' world cruiser you think you want, get a boat you can afford and sail today. You do not know yet what you want, experience will help you find out.
See the Dreamers v. Doers thread: Dreamers vs Doers
. My best advise is to be a doer.
Also, sailing is only one component of seamanship. Reading cannot supplant experience, but it will give you a foundation to learn the basics. Consider the Annapolis Book of Seamanship: http://www.amazon.com/Annapolis-Book.../dp/0684854201
, there are plenty others too, but that is a start.
This is a friendly board with many knowledgeable people, as you have more questions, let us know. Welcome to sailnet. You may want to post your location, there may be local people on this board to help you get going.