Balance being responsible with being a pest.
Following up after applying for a job or setting up a meeting is a good habit to follow. You can do this by calling two days after you sent in your resume to make sure there were no problems receiving it. This is also a good time to ask to set up an interview.
It’s also good practice to confirm meetings beforehand. You can send an e-mail the day before or the day of just saying “I just want to confirm out meeting is set up for (day) at this time (time). Looking forward to meeting with you. Thank you.”
There comes a point where you need to stop and let the other person have the responsibility of getting back to you. Follow up a couple times, then leave the responsibility up to the other party. Leave them an easy way to contact you. When they’re ready and if they really want to, they will contact you.