Don't strike out before you start.
Job search is a state of mind, not an activity. What does that mean? It means that when you are looking for a job, in the back of your mind should always be, "What if a hiring manager could see me right now?"
This may seem a bit extreme, but there are countless stories of huge mistakes people have made, killing their chances right out the gate.
There was a guy that I called to schedule an interview. He looked impressive and I wanted to move quickly so he wouldn't be hired elsewhere. I called him at around 3pm on a Thursday and he picked up the phone on the second ring. "YO!", he said. There was a loud racket in the background, lots of people talking and...was it a bowling alley? I introduced myself and he said, '"Oh, it's kind of loud, can I call you back?" He asked for my number and asked me to repeat myself three times. Was he drunk? I was irritated when I hung up, and didn't bother following through with an interview.
Any time the phone rings, it could be a hiring manager. Hiring managers may call you after dinner, or on the weekend, any time at all. Don't pick up the phone if you don't recognize the number. It is perfectly okay to let the call go to voicemail. Within the next few hours, listen carefully to the voicemail and make a note of the person's name and number. Then look up the job description for the job they are calling about, and review it carefully. Write down questions that you have about the job, and review the company website. Have everything ready and sit in a quiet location where you can have a professional, uninterrupted conversation. Then call the person back.
These steps will help ensure that you have a chance of being brought in for an interview.