How to use your eyes
Print out large samples of a few typefaces. Look at them all day. After a while, you may start noticing things you hadnt before.
How many curves make a comma? These four are from Bodoni, Times, Helvetica, and BriemAkademi. The concept is simple. Each shows a different approach.
When you struggle with an stubborn problem, ask yourself this. Hasnt somebody found a solution already?
Learn from the masters
Do you want examples of proper digitation? Bigleow and Holmess Lucida demonstrates that all typefaces arent created equal. Craftsmanship still lives. (But for a good laugh, look at the digitation of early Helvetica releases.) Select designs you trust. How thick should you make the hyphen? What is a good height for parentheses? Dont reinvent the wheel. Go and look.
Dont get me wrong. Im not suggesting you trawl through type catalogues, purloining from your betters. Let me show you what I do have in mind.
A close shave
The letter d in the design Franklin Gothic doesnt at first glance seem an exercise in subtlety. Look again. The white wedge-shape, where the lower part of the bowl joins the stem, has been cleverly augmented.
This enlargement shows the curve meeting the stem. Simple logic would place the left side of the stem at the thin vertical line. The small retreat to the right is no accident. It is quality work.
See also: How to imitate spacing.