Lettering well takes a lot of practice. But a trick to getting your lettering up to snuff fast is to use a straightedge to draw the vertical strokes. It will make them perfectly straight and give a polished appearance to your lettering. Use a small triangle or the Ames lettering guide, and make sure it rests squarely on the parallel bar.

Freehand the horizontal strokes; slanting them a little makes them look good.

This photo is from my book Architectural Drafting for Interior Designers.