1. Turning off without shutting downYears ago it was actually possible to damage your hard drive by simply turning off your computer rather than shutting it down. Technological advancements have made that risk negligible. However, turning your machine off can still cause data issues. If you're in the middle of a critical operation, such as a software update, you can cause big problems by cutting the power. Think of it like performing open heart surgery and then turning off the heart bypass machine in the middle.
2. Opening emails/attachments/links from an unknown sourceWhen you do this, it's like licking the handrail descending the steps into a subway. If you get sick, it's your own fault.
It's generally not entirely possible to completely ignore emails from people you don't know since email is such a ubiquitous form of communication. A couple of rudimentary ways to weed out the illegitimate emails: Does the sender address look real? Is the sender name properly formatted? Is the subject about sex, trying to sell you something/asking for money, or promising a prize?
If you open an email, do not open attachments unless you know the sender. Do not follow links unless you know the sender. Even if you know the sender be wary if the content raises any flags such as unusually bad grammar or advertisements, solicitations, etc. Before following links, make sure they point reputable domains.
3. Not saving often or creating regular backupsThe universe conspires against you when you're working on something vitally important and under a tight deadline. It's not just in college. Backing up data has become so much easier in recent years. Many routers now have simple to use network storage options for USB hard drives. Dropbox, Amazon Cloud Drive, and Google Drive have very simple solutions for storing your data in the cloud. They work automatically once configured and you can access your stuff from anywhere. I recently started using AeroFS which allows you to create your own private cloud on your own hardware. It's very simple to set up and use. While it lacks the web file browsers of the aforementioned cloud drives, there is no monthly service fee (for up to three users) and I'm only limited by the size of my hard drives.
4. Using insecure passwordsPasswords don't have to be hard to remember in order to be hard to crack. Several years ago, Thomas Baekdal wrote a great post about this, which can be summarized as put 3+ random words together. That's it! "Windows ostrich Mountain Dew" would never ever be hacked but is easy for me to remember: my OS of choice, my blog, and my fuel. Of course a lot of sites that require a password are lame and would say that's not secure, even though it is. So come up with something shorter and make sure to use a capital and a number. "p1anoplayYes"
UPDATE: What makes a password secure just got more complex. This post at Ars Technica explains how hackers go about figuring out passwords. Page 3 of the article is particularly revealing.
5. Not installing updates as they become availableInstalling updates can be really annoying, especially Flash. It seems like they always pop up at the least convenient time, you never know how long they'll take, and they often require a reboot. So we don't install them. Updates keep your system and applications working smoothly and, more importantly, securely. Failing to install updates is like having your front door smashed in and you just don't have it repaired. Sure you know everyone in your neighborhood by first name but that doesn't mean you're safe. Just do it though. Maybe not the minute the notification pops up, but within a couple of days. If you do it at the end of the day, it won't inconvenience you.
6. Not keeping up with changing technologyI'm talking to YOU, Mr. Still-Running-Windows-XP (or old version of OS X). For one, you're opening yourself up to security vulnerabilities that Windows 7 and 8 (or OS X "moon cat") protect against. The longer you wait to adopt newer technology, the harder it will be for you to adjust. You'll have a better user experience, guaranteed.
7. Being an early adopterWait, didn't I just say to keep up with new technology? Yes I did. What I'm saying though is that it's okay to wait for the technology to become mainstream first. Jumping in early can cause at least three different issues.
- Remember HD-DVD? Some technology fizzles out before it goes anywhere.
- Sometimes the technology isn't quite ready for big time when it's first released. Windows 8, for example, took the OS in a completely new direction. The visual design is gorgeous (definitely 10 years ahead of the ugly, out-dated OS X), but even I think the the user experience is disjointed. Windows 8.1 is hopefully going to make that a lot better.
- New technology usually costs more than established tech. Sometimes it's fun to be on the cutting edge, and there's nothing wrong with paying a premium to have the latest and greatest, just don't be ignorant of that fact that that's happening. Sometimes waiting can save you big bucks.