Step 1: Research
Read as many magazines and books as you can. Every build up article and feature, look at all the rods at the runs. look at all the shop visits and check out what and how they're doing it.
Get to know all there is to know about your particular make or model, how they were constructed , how they performed, what were their weaknesses.
If you find yourself clsoe enough to the owner of a rod similar to one you are building go up and introduce yourself, tell him what you are doing, chances are he's just dying to tell someone what he's done.
Take photos of rods you like, analyise what you like about them. Is it the body or the grill, the motor, the stance or the colour. There are many unique features that make up a hot rod.
Start you own scrap book with all the details about your hot rod. It will make it a lot easier to explain to someone welse who will be working on the car if they can see what your all about. It's the old classic, only in the case a picture may be worth 100 hours if something goes wrong or has to be re-done.
If there is one thing you can know for sure is that it's gona cost more to build than what you think.
See Build to a Budget - Savings