Sorry for butting into your life-style. :notworthy: I took down the last paragraph of my previous post because I want to be helpful, not hurtful. I guess what I'm trying to say here is that given your driving conditions, 13mpg is not unreasonable. A very few miles per day with multiple stops, and apparently you're carrying a load of tools -- that pretty much the formula for poor fuel economy no matter what you're driving.
As for your original question, you can maximize your fuel economy by accelerating slowly and anticipating stops well in advance. If you have auto-stick you can keep your RPMs down by nudging it into the highest gear it will take. Also keep your plugs new -- under your driving conditions they're going to foul much earlier than most. Traveling so few miles per day, you might even consider using fuel stabilizer.
Might be too late now, but next time around, maybe consider a hybrid vehicle? Those are designed for short-range stop & go driving. As much as I love my Patriot, it is not the best vehicle for every owner in every situation, and it might not be for you.
On the bright side, I really don't think anything is wrong with your Patriot. I wouldn't waste your money trying to fix what's probably doing the best it can. If you were driving 100 miles at 50mph and still only getting 13mpg, then yes you'd have a problem and probably someone on the site might be able to offer good advice.