Most important rules for producing high quality drawings.
1. Text Height
All drawing notes, dimensions and leaders should have the same letter size regardless of the scale of the drawing. The best letter size is 2.5 mm. This means that when you print your drawing and take ruler to measure the height of the numbers and letters they should measure 2.5 mm in height.
For the drawing title you can use 5 mm and for naming the grid lines 7.5 mm. Theses three heights (2.5 mm, 5 mm and 7.5 mm) are more than enough. Check the article "Text Sizes and Font" for information on how easily maintain the same text size independently of the scale on which drawings are plotted.
2. Text Font
Font is not important. You can use any font type you like and the results will be very good provided that the text font and size is everywhere the same. Be careful! Use everywhere the same text font.
You should print only monochrome drawings. All lines and notes on the drawing to be in black ink.
Do not print color lines for your drawings. Also, do not use grey or other tone of black. The reason is that you can not re-produce such drawing unless you have color copy-machine. The contractors and subcontractors that will use your drawing will probably copy the drawings. When coping colored or grey-line drawings only black lines are clear. Colored and grey-tone lines will not look OK.
The above 3 point will make a drawing look perfect. Those those point are what separates the professionals from the novices.