Since i can not possibly cover everything, and also since a lot of the learning comes with experience, you will need to do some research and experimenting on your own. Building a longboard is not a simple task and it requires patience, hard work, and attention to detail.
Hopefully i can share with you what i know, and what has worked well for me, so that you too can start making boards for yourself, and maybe even friends.
If you are really new to this, you might not even know what longboarding is. If you have no idea what longboarding is, then i would refer to this instructable first: http://www.instructables.com/id/Longboarding-what-is-it/
Ok you want to build a longboard!
Here are a few things to keep in mind:
Longboard building is not cheap, but if you do put time, care, and effort into your boards they will last you a long time. Your first few boards will probably break as mine did, but once you get it down, you will have lots of boards to ride, and possibly sell. I would recommend starting out with a simple design and then move onto more complicated designs once you have board making down.
Please note: The instructions and techniques come from all different sites and i am just putting it all together into an instructable. I am not stealing the information, i am using what i know wand what knowledge others have shared with me.
Here is a good website to help you with building if you get stuck.
Finally: *I am not responsible for any injuries, build boards and skate them at your own risk. Please always wear the proper safety gear when skating*