A helpful thing to do before even beginning the build is to draw a full scale (meaning full size, as in 1:1) drawing of the instrument you have in mind.
Good reasons why the full scale drawing is the first thing you should do
1. You get an initial feel for the guitar
While true the guitar only exists on paper at this point, the 1:1 drawing gives you a sense of size. You can take this drawing an examine it on the bench or on the wall, horizontally or vertically.
2. You spot potential mistakes very early
When you put the idea in your head to paper and examine it at full size, chances are you will spot a few things where you will say to yourself, “that doesn’t look right”. You can then correct the error(s) you see on paper before even beginning the build.
3. You can experiment with shapes before building
An example of shape experimentation is deciding whether to go with a single or dual cutaway shape. This does not require two completely separate drawings. You can draw the entire guitar first using the single cutaway shape, then tape a second piece of paper on top of the completed drawing and rough out your dual cutaway on the upper portion of the body.
“I have absolutely no idea at all how to draw anything and just need a guide”
If that sounds like you, what you need is a bass plan.
There are full scale plans out there for purchase. While we don’t sell the bass plans, there are others who do.
You can find an acoustic bass guitar plan here: http://www.luth.org/plans/instrument_plans.html
Some extra tips
Find out where your local copy shop is
The copy shop will probably be the only place where you can make large format copies of your 1:1 drawings.
Need to destroy a copy or two? Do so if you have to.
When you have only one copy of your bass design drawing, you don’t want to ruin it because that’s the only one you have. When you make copies at the copy shop, this allows for more freedom, because if you have to destroy a copy when making drawing changes, you can do it without worry since you have an unaltered copy of your original.
Where are the rest of the build steps?
You can view them all here.