One important thing (for me, at least) is to have a clear goal; you need to know from the start what you want the end result to be: resto, rat-rod, daily driver, fast rust-bucket... as well as some work/mods you really need. Write down this goal.
It is also good to find some pictures of vehicles you like in the style you want (don't have to be the same truck, just the same feel...) and look at them often to remind you why you do this and where you are going.
Without this, I tend to be carried away on side things on my vehicle which actually do not help the project move along: oh, if I did that, or this... It may seem like a good idea at the time, but it is not needed to get you to what you really want...
Example: if you just want to have a plain, simple daily-driver, well, do not spend 3 weeks shaving the door handles, even if one day you thought it would be cool.
And yes, as mentioned earliest, please only work on 1 vehicle at a time!
Good luck!
