How to follow up after applying for a job?

There is not a hiring manager like there is with most companies and I was wondering how I could follow up to try to make sure I'm considered.

I applied the first day the job was posted, its been two days now. Should i call or wait till Monday to ask if they have had a chance to look at my application?

I applied for a job online yesterday. I was planning on calling today, but is it too soon?

I've had my current job for about 6 months, and am applying for what is basically the same job, only with more consistent hours. I don't know if I should ask a co-worker to serve as a reference (seems kind of impolite, given that I'm not the only person...

I am 15 and I just applied for a job at a small restaurant. They had a "help wanted" sign out, so they needed people obviously. The restaurant does not serve alcohol so I could be a waitress if they needed one, I said in my application that...

I filled out an application for a delivery driver at Advance Auto Parts. I stopped into the store at 7 am (store opens at this time and just to show that I can be on time). I spoke with a worker about certification that is required for such position...

I sent my CV to a company through totaljobs.com and they sent me an email saying that they have sent it to the company but 'Totaljobs.com does not take part in the selection process; please contact the recruiter directly at __(email of company)_____...