It's a serious undertaking when you restore a car, the biggest part of it is to be prepared for anything, if your doing it yourself then make sure that you have a good system for cataloging the parts that come off of the car that your doing, and be prepared for the un foreseen, it's a lot of work and a lot more time, it never a quick venture.
Make sure that you really love the car that your restoring, because if you don't it will probably get boring and monotonous, and that is the last thing you want to happen, this is how people end up with half done projects, and cars that they hate, be prepared with the money that you'll need to do the project, and it won't be just a little bit either, it will be a considerable investment of time and money.
Don't fall in to the old trap of thinking that the car is in good condition because of what it looks like on the outside, this can be very deceiving, be sure to look at everything from the inside out, most cars have a lot of hidden work that's not seeable from the outside, so be sure to open the trunk and look at the floor of it, pull up the front carpet just a bit and look at the main floor board of the car.
On the out side look for bubbles in the paint on the car, this usually indicates that the paint has rust underneath it, look real hard at the rocker panels of the car, and around the rear wheel wells, and always look under the wheel wells at the rear outer wheel well, open the hood and look at the engine compartment for rust, and bad wiring, these are tell tail signs that the car will need a considerable amount of work to make it drivable.
Id your planning on having a shop do your restoration for you, then be prepared to give them what they need to restore your car, as I have said earlier, you will be spending a lot of money to restore your car, so be prepared, a shop will need parts on a regular basis until your car is done, and they will need paint supplies, and a lot of other things, and most shops don't have the space to store your car if no work is being done, so give them what they need to build your car.
A restoration of a car that's in good shape will usually take about 900 hours of work, and if the car is in bad shape it can take a lot more, but remember that you get what you pay for, if you want the car done really fast they will need more then one person working on it, and this will mean that you'll be charged at the shop's labor rate for each person working on your car, if you can wait and you have some time to complete the project, then you will more then likely save some cash.
Most shops will try do restore your car for the best price that they possibly can right at the first, so bargaining with them to lower their prices probably won't work with most shops, the shops don't make a high profit margin on their work and usually can't afford to be cutting their prices, and in most cases shops don't do estimates, due to the fact that it's pretty much impossible to estimate a restoration project because there are so many variables that enter in to it, it's a lot different from a collision repair shop.
In a restoration there is no standard for the time that it takes to perform a certain task, and it is impossible to know what's rusted or damaged in the car until you start the project, the shop has to tear in to the car to find all of the defective areas of it, and this can't be done without bringing the car in to the shop and putting a man on it, it's never just a matter of a simple looking at the car, it a matter of locating everything that has to be done, and it is never an easy job.