I'm a pretty good parallel parking, my whole family will let me park the vehicle if I'm with them because I get it done in a fraction of the time it would take them. Never had to explain it over the internet though, so this might get difficult.
If there is a car parked infront of the parking spot you are going for, pull up next to the vehicle. Put the vehicle in reverse, and turn the wheel so you are backing up and turninig into the parking spot, Keep your eye on the sideview mirror, when you can see the entire front end of the vehicle behind the parking spot you are trying to park in, Turn the wheel the other way so your front end starts pulling into the spot. If done correctly, you should now be parked nearly perfect in the parking spot.
Adjust the front or back end accordingly, but for the most part, You should be good.
Obviously it would be alot easier to show you in person, which isn't possible, so I would just say look online for Youtube videos, of check locally for Driving Instruction courses, they tend to be cheap (sometimes free), and they'll help you with anything you need.
I've had my license for almost 3 years now, and I passed my drivers test on the first try.