97 things every programmer should know

is an excellent book edited by Kevlin Henney (isbn 978-0-596-80948-5). As usual I'm going to quote from a few pages:

Pay off technical debt as soon as possible. It would be imprudent to do otherwise. Seb Rose

Users don't think like programmers. Giles Colborne

Comment what the code cannot say, not simply what it does not say. Kevlin Henney

Deliberate practice is not simply performing a task. If you ask yourself "Why am I performing this task?" and your answer is "To complete the task," then you're not doing deliberate practice. Jon Jagger

the Golden Rule of API Design: It's not enough to write tests for an API you develop; you have to write unit tests for code that uses your API. Michael Feathers

Professional programming is usually not like running hard for a few kilometres, where the goal can be seen at the end of a paved road. Most software projects are more like a long orienteering marathon. In the dark. With only a sketchy map as guidance. Olve Maudal

What are you working on right now? Is it all needed? Pete Goodliffe

By making sure that the build is always clean, I will not have to decide that a warning is irrelevant every time I encounter it. Ignoring things is mental work, and I need to get rid of all the unnecessary mental work I can. Johannes Brodwall

An estimate is an approximate calculation or judgement of the value, number, quantity, or extent of something… A target is a statement of a desirable business objective… A commitment is a promise to deliver specified functionality at a certain level of quality by a certain date or event… Giovanni Asproni

If your project is apparently on track, and one week later it's six months late, you have problems - the biggest of which is probably not that it's six months late, but the invisibility force fields powerful enough to hide six months of lateness! Lack of visible progress is synonymous with lack of progress. Jon Jagger

Sometimes the best thing you can do to solve a problem is to put the mouse down and step away from the keyboard. Burt Hufnagel

The Singleton Pattern… What's not to like about this classic design pattern? Quite a lot, it turns out. Sam Saariste