The following is painfully honest advice from someone who has done EVERYTHING on this list wrong. Please avoid the pitfalls I describe here and follow my advice! I wish someone had advised me like this when I was 22!
As I advised on the Technology Tips article, having a professional email address is vital. How vital? Well, let's just say I've lost a few job opportunities because my prospective employer emailed me back laughing about or mocking my personal email address. You REALLY don't want that. Here are important tips to follow for creating your own professional email address:
While going through college, try to have at least a part-time job--either do work-study on campus, or get a job close to campus. It will be harder to get classwork done, but at least you will have job experience when you get out, AND you will help pay for your own college education, too!
To compensate, take the minimum number of class hours needed to be considered a full time student, so that you're not overloaded. Also, PLEASE avoid Writing-Intensive classes unless you're an English major. (If you are an English major, take no more than one Writing-Intensive class per semester. Please take it from me, an idiot who took THREE Writing-Intensive classes in one semester. Craziest schedule ever. Don't do it. Bad things happen.)
When you work, whether it's a volunteer position or paid work, DOCUMENT EVERYTHING:
I CANNOT STRESS THIS ENOUGH (and I am so angry with Past Me for not doing this)!
Seek out any and all internships through your college whenever possible. Work connections with professors to see if they know of any local internships or even paid jobs in your field that you could take on. Document this as thoroughly as you document your paid experience--who knows, a little internship you had one semester could become the thing that gets you paid work later!
Never let a college summer go by when you're not either working for pay or doing an internship. Get that work experience while you're off school! I CANNOT TELL YOU how frustrated I am with myself for not doing this. I do believe in giving your brain a rest from studying and exams, but I shouldn't have just knocked off for eight to twelve weeks either. (LOL)
Keep a running updated list of your references on Google Docs so that you can reference it easily through the app while on the go. (This helps SO MUCH with filling out job applications on the spot.)
Also, make sure to have all your work records and references with you before you start filling out applications. Whether you're filling out applications in person or at your computer at home, this will take a lot of stress off your mind. (You can put these records in Google Docs or have paper copies--whatever works best for you!)
Before you list someone as a reference, call/email them to make sure it's okay, especially if you haven't talked to them in a couple of years. They might not remember you otherwise. Also, check with them to make sure your contact info for them is up to date.
If you're feeling anxious, depressed, etc., please seek mental health care while you are still in college. Don't get out into the workforce and get destroyed first. Take it from me, who suffered 25 years with undiagnosed PTSD before finally going and getting it treated. Normal people don't feel paralyzed by fear all the time; normal people don't calmly think about suicide as a viable decision; normal people have no idea what depression or anxiety feels like other than assuming it feels just "sad" or "scared." Your thoughts can become as diseased as your flesh, so get those negative paralyzing thoughts treated! (Don't forget to practice good self-care afterward to prevent them coming back, too.)
If you have any form of long-term illness or disability, whether physical or mental, there may be services in your area that can help. I went through a service called "Vocational Rehabilitation" to find work while I was still recovering from PTSD and a herniated disc. Google around, ask around, and see what you can find! Your region's particular job assistance service may not consider you eligible, and it may not be called "Vocational Rehab," but it never hurts to try!
If you just can't find any paid work or internships in your field, start doing some sort of related service in your field for free. Document everything (as mentioned above), and who knows, that could lead to a paid job in time--but not if you keep bad records or none at all!