This is my first post as a TRDPI member, so I'll try and make myself useful.
If constructing your own guitar, obviously it is easier to buy templates such as those previously mentioned by Woodman1, which I understand are excellent.
A second option is to borrow a mate's Tele and do some measuring and tracing.
The third option is to build the guitar from information available on the internet. That is what I am currently in the process of doing (I don't have access to a Tele). The following is suggested:
Go to website http://www.guitarbuild.com
. There you will find a downloadable CAD drawing of a Telecaster. Download that to your computer. The file format is .dxf which is a format used to exchange drawings between CAD programs.
If you don't have a CAD software program (I don't), the good folks at DWGSee (they have a website) will allow you to download their excellent software for a 30 day trial which you may wish to try. The software will open your previously downloaded .dxf file.
Unless you have a plotter (a printer which prints honking big sheets), you will need to use a standard printer and print off the drawing in sections which you can tape together to make a complete drawing. I used five 8.5 by 11 inch sheets to cover the body area and then taped the prints together. To ensure that I was in the ball park on the body size, I measured across the lower bout which came out at 12.625 inches.
Before people start writing in to tell me that my body measurement is out by X, please note that I am willing to bet that if one took a bunch of Leo's early Teles and measured them there could be up to a .25 inch difference across the lower bouts because of the human interface in the spindle shaping and sanding process which produced them. Not like today where a drawing goes electronically from CAD in the USA (or wherever) to a CNC machine in China and not a millimetre gets lost.
Make two sets of prints, one as a working copy and one as a spare to have copied the next time you are near a large photocopying machine .
Cut the excess paper from just outside the body outline on one print and glue the drawing to a piece of .25 inch plywood (you only need to glue around the perimeter). I used some scrap poplar floor underlay which is soft and easy to sand. Cut the wood with a jigsaw to just outside the body line and then sand the wood down to the outline on the drawing. To do this, I mostly used my belt sander resting on its side on a table. For around the neck area, I used a drum sander chucked into my drill press. The final finishing is by hand with sandpaper on a soft block. Your fingers will tell you when everything is smooth.
If you make a mistake, it is easy to glue a small piece to your plywood and rework it. I did cut the neck joint area too short but have simply glued a bit of wood back on and reworked that area. When I am satisfied with my template, I will use it to cut a working template from hardboard using a router.
From the position of the hardware shown on the drawing, it should be reasonably straightforward to calculate the various body routings when one has the hardware. When I make my hardboard template, I will make an additional one for the body routing.
I am currently getting together the wood for my first body. It will probably be pine as I have some pine available at 1.25 inches thick to which I will add a.5 inch cap.
I will post a couple of photos when I have my picture hosting sorted.
Hope this helps.