This isn't a very hardcore developer tip, but it can significantly affect productivity and communications: Learn how to type properly.

A good portion of two-finger typists, when advised to do this, will reply that they can type faster than any "formal" technique already, often referencing dubious online tests that affirm their mastery (claiming some ludicrous number to go along with their 170 IQ). It's highly unlikely - not impossible, but unlikely. I say this with inside information, as I, too, started as a two-finger typist, teaching myself all the wrong techniques on my Atari 800XL. I became so confident in my mastery that in my first year of high-school I signed up for a course called "keyboarding" - basically training for a classic prototypical 1970s secretary (learning margins, various letter layout standards, and of course typing...err "keyboarding"). It satisfied the need for a business credit, and I figured it'd be an easy period, so there I was.

This course taught proper form, and it was no time at all before I was typing with the best of them. My accuracy and speed increased dramatically, and I could spin off paragraphs with a minimum of fuss and spectacle. So much so that they sent me to the county-wide business "Olympics", where I won the lucrative and heavily sought after typing contest. How nerdy is that? Yes, very.

Of course the rate of data entry for software development is hardly the limiting factor when you consider that most developers complete a couple of dozen lines of code a day (averaged over a year, and that's actually overstating the average): Instead good development often entails a lot of research, planning, and thought, and a minimum of actual coding. Nonetheless, once you factor in communications (e.g. emails, IMs, and so on), comments, and documentation, the average developer actually types an enormous amount of information into their PC every day, and the capabilities of their person-machine interface becomes extraordinarily important: The last thing you want is negligent documentation, deficient comments, or spartan and poorly communicated emails, all because one can't efficiently and effectively turn their thoughts into digital form.

So if you want to maximize your ability to use this medium, and reduce the amount of shock and awe (and time) required to convey a point, make sure you're using proper form when you're typing. Don't get bogged into debates over Dvorak vs QWERTY to justify poor form -- just pick one and do it right.