If you want to get this achievement out of the way early just do level 14 over and over. You need to build 3 towers using the 3 special blocks. If you don't make any mistakes you can do the level in under 30 seconds. To build the 50 blueprints you need to build 50 towers, so you will need to complete the level 17 times.
This all must be done in one session otherwise your count to 50 gets reset.