Using the mother of all drawing packages to create beautiful house blueprints.
Getting the app
AutoCAD is the gold standard for a Windows engineering drawing app. It is an incredibly capable program. For the drawings that will be worked on by your structural engineer and for the blueprints that you submit with your building permit application it is best to use AutoCAD.
The bad news is that it costs thousands of dollars to buy a copy. Luckily they make a fully featured 30 day trial version available for free. If you are a quick worker and can get your drawings done and printed within 30 days, you could theoretically just use the 30 day trial version. The reality is that there will always be future mods to the drawings and so the 30 day limit is eventually going to be a problem. One solution might be to do the bulk of the drawing work yourself within the 30 days and then subcontract any small modifications to a design house that does own AutoCAD (almost all design houses use AutoCAD). Or of course you might decide that it is worth the few thousand dollars given that it is such a good app.
It is NOT an option to get a full time student to do the drawing for you. It is the case that full time students can get a free license to use AutoCAD, but the educational version they get produces a watermark on your plots that cannot be erased. Even if you import just one small library block that was done on the educational version then this will infect your entire drawing and from that moment on your drawing will be useless.
Top level technique
All one drawing
It is best to do all your drawings as one drawing file (a .DWG file). Use layers for the different floors and then more layers within each floors for the different types of things on the drawing.
Snap to Grid
It is a very good idea to keep the snap to grid feature turned on all the time. You can keep adjusting the resolution in order to keep it as course as possible consistent with drawing the detail you need at any particular time.
Items that are used frequently in multiple places should be drawn as Blocks that you can name and allocate a reference point for. Blocks should be created on Layer0 (this lets them inherit properties for the layer they are inserted on).
Everything needs to be exactly accurate so you can get exact distances of the drawing. Given that the EPS of the ICF is 2-5/8" rather than 2-1/2" then that means that you will need a drawing resolution of 1/8". Note that you can vary the drawing resolution as needed so you will typically operate with 1/2" resolution and then drop down to 1/8" to make adjustments as needed.
Tips and tricks
Samples of my drawings