It become very easy in Qatar now to renew resident permit by various options,
1. By Metrash 2. or
2. Personally go to any immigration center (Gharaffa or Messamaier).

I went with option-2 to one of the center, carry the passports of your family members along with you for verification, if you have baby infant carry one photograph.
Pay the monies by your Debit/Credit card and your RP is renewed.