10 pearls of collected wisdom for the aspiring terminal/console/command line user. This assumes UNIX but little actual command line experience.
1. Customize your your .bash_profile or .bashrc files and continue to tweak this file as you learn more about how you use the shell. I even have a line in my profile that makes it easier for me to edit this page.
2. Never open files unless you have too. tools like less, more, cat, and grep should be enough to keep you going for most routine checks.
3. Having said that, getting to know your text editor really well should be on the top of your list of things to do. There's something to be said for learning how to use vim, though I can understand if you might want to use something a little less sharp around the edges.
4. It's good to be able to hack your way through bash/shell scripting and at least one other general purpose scripting/programing language. Like Perl or Python, but Ruby and PHP would work. Power users don't necessarily need to be able to write brilliant programs, they just need to figure out how to glue other programs together.
5. Familiarize yourself with your operating system's package manager, or get macports if you're on a mac. Or get an operating system with a better package manager. To my tastes this means means getting a debian-based linux distribution, but there are others if this won't work for you. These package installers make it so much easier to install software and have it work because other people do the testing. Compiling things on your own is ok, but package mangers are better. Learning how to use the cpan shell and ruby gems falls under this imperative.
6. Do first and script second. While you may be tempted to write nifty little scripts for all the things you think you're going to do, don't. Work first and figure out what your habits are and then write the scripts/macros/short cuts that will best serve you. That way you'll use them.
7. Figure out how to schedule tasks/automate background tasks. If there's an internet connection, and probably even if there isn't, my computer checks my email every 8 minutes or so. Because I have a little "check email and tell tycho if there's anything new" script set to run in a launchd deamon. You could use cron if you're not using a mac, but the general idea is that if there are things that you know need to be done, regularly, you just tell the computer to do them, and then you don't have to worry about it.
8. Read the manuals and google for help, but also relax. The terminal lets you do a lot of new things, and it saves you a lot of time. It's also hard to learn and a lot of die-hard terminal users are also, to be blunt, assholes. I don't want to recount the number of times that I've seen people rant on about proper forum, and how new folk ask too many questions. This is dumb, new people always ask questions, and the truth is that some things aren't well documented. Also a lot of terminal assholeishness comes from a period of time, when certain operations took a lot of CPU power, and CPU power was more at a premium than it is today. Most contemporary computers, even ones that are a few years old, run so fast that even inefficient terminal applications still run incredibly fast on modern hardware, and can outperform the best GUIs. You'll learn later.
9. Remember the Unix Philosophy. Basically that programs should do one thing well, and not complicate themselves with doing more than one thing. If you know that this is how things can and should work and you can learn how to work with this, then you're in good shape. (It's also ok to bend it a little bit, from time to time.) Also, if you're an oddball like me--and using the command line for something, like writing fiction--slowly get a sense of what existing tools do, and figure out if its useful to you. Also know that just because something's cool it doesn't mean that it's going to be useful for you.
10. Customize the appearance of your console window. Apple stocks everything with an ugly black text on white background thing, which makes my head hurt from the squinting. Readably sized fonts, good coding fonts, anti-assailing, colorizing your prompt, light text on dark backgrounds, and some transparency all make the terminal more functional and elegant.