I need help on making doorways and windows for my buildings. the overall building is going to be about 8" length wise 5" height by 1/2" width. The main wall has 3 windows on the second story. 1 door on the 1st story followed next to 2 windows the same size as the windows on the 2nd story.

A simple method is to first figure out the scale size of your doors, and then do the math conversion to get the right meaurements. One you have this done and have cut out the openings, you can use wood, plastic strip, or even plaster bricks to create the casings, moldings, and trim.

If you don't have a scale conversion ruler, remember that a typical 5'9" man is 69 inches tall..... and in 1"35 scale is roughly 52MM tall.... so a 7 foot door (84 inches tall ) would be close to 63mm in 1:35 scale. The formula is (84 x 52) / 69 = 63.3

As for Windows, often use GrandtLine plastic windows which are cheap, easy to work with, available in a variety of sizes, and quite detailed.

Another nice way to make doors and windows is with wooden strip, available at most any major hobby shop or craft store. Just a little white glue and a sharp razor, and you can create about any shape or size needed.

Hey 19,
When I construct buildings, I like to use a 1:35 figure whiloe I'm building just for a comparison to make sure everything looks "right". Even if you use scale measurements, things don't always look quite on.
Also, if you want to get real detailed, check some of the DIY webstes to see how doors and windows are constructed. It helps if you know how the real deal is put together.
Oh and for window glass, I use those @#$%% blister packs that kids toys come in. The ones that you need a knife and small amounts of high explosive to open. It's nice and thin, and lends itself well to be cut for broken window panes and scribing cracks. Looks very realistic.

Another great idea for window panes... use Printer Transparency sheets... these are clear plastic "pages" designed for printing color foils and overhead projector images. I use Hewlett Packard brand, available at any office supply store.

The neat thing is I can load the sheets into my printer, then use a graphics program to create window signs. I cut them out, and glue them into my dioramas... great way to make "stained glass" for a church as well!