Use fixed-width fonts for data entry fields
But there's a point hidden down at the end of Chapter 7 which is well worth repeating. And that's that using a wide fixed-width font for text entry is much better than a thin proportionally-spaced font.
Recently I noticed that the invitation panel on Google Spreadsheets, allowing you to type in email addresses of people to invite to collaboratively edit the document, used a fixed-width font. And conveniently they didn't alter their word processing program's similar facility, making it easy to compare the two.
It really does just feels so much nicer to enter text using a fixed width font. So all projects I'm doing now, I make sure I use a fixed-width font for data entry. And I don't even think it has to look ugly!