You used to be able to pay it online at the e-Government site but that's been under maintenance for a long time now. Go to the traffic department either at Madinat Khalifa or Airport to pay.
You need to renew your car's road permit once a year. That's when uou have to do a traffic violations check before they renew the permit.
Fines don't increase. You just have to pay it when your road permit is up or if you're involved in a car accident; they check for violations then.