I use my Insight for pizza delivery driving, and am averaging mid-60s mpg in the winter and close to 80 mpg this summer. EPA is 48 city (think it was 61 city before the new ratings...).
You have a manual. Engine off coast down all the hills and when you're braking to a stop. Minimize braking, coast when you can to stops, but don't take coasting too extreme because you're on company time and need to be time efficient as well. Above all don't race to stops and slam on your brakes! That is the number one thing that kills people's city fuel economy. Car off as you approach all lights and intersections. Memorize the familiar roads and learn to drive them efficiently without wasting time. Slowing down helps economy a lot, but there are plenty of other driving techniques you can implement to improve economy without slowing down, especially in a manual transmission car.
Mount your pizza delivery sign as close to your front windshield as you can to minimize aero penalty, which is huge. Avoid taking the highway on delivery runs if you can - most company signs are terrible for aero. For example, I've used my mom's Prius for delivery driving occasionally when I've been working on my Insight. On the highway with the delivery sign the Prius only gets 36 MPG at 70 mph. Whereas if I stick to 59 mph or lower around town, just yesterday I got around 54 mpg delivering in the Prius.
With extensive ecomods I got close to 40 mpg delivering in an '04 Civic I had, which is pretty comparable to your Corolla, except that you have the advantage by having a manual transmission.
Air your tires up. Take them to the max sidewall, usually 44 PSI. If you want to be adventurous, run 60 PSI. Don't run 80 PSI like I do.
At the lower speeds of driving, rolling resistance plays a huge factor in economy, often more so than even aero. Airing up your tires makes them more efficient and reduces your rolling resistance, thus improving economy.
Also follow normal driving techniques, i.e., always drive in the highest gear possible. Unless I'm at 30+ mph where I can lean burn (unrelated to this, but it's a pretty cool thing) the Insight is driving at 800-1000 RPM in the highest gear possible without lugging the car.
I predict you should be able to break over 40 mpg delivering, and get around 50 mpg in all other driving.
Also, welcome to Ecomodder.