I'm an experience rider who just came back from a 2 year absence on riding. The basics. 1)your brakes will have shorter lifespan because of your weight. Always check the entire set up of the breaks, from wires, to pads, to levers. Make sure they are completely stable and ready 2) tires for heavier people not only wear out faster, but they get punctures much easier(since the tire presses down harder on the ground, the contact surface area becomes greater). Check the pressure as well. Under-inflated tires will cause the rim of the wheel to be closer to the ground. That's problematic because the closer a rim is to the ground, the less control you have. This is due to the fact that rubber has a spring-like property which expands and contracts. When it is properly inflated, it is rigid enough so the contractions are minimal while elastic enough to provide a smooth ride. And as for new riders, always ride on the street, sidewalks are dangerous for pedestrians and cars exiting a driveway. The best way to get to know a road is to ride it. Google Maps and Strava are good but sometimes a road might not be for you, it might be too steep or too many obstacles. Anyways make sure you ride before rush hour, I find this to be before 1pm and after 630pm, assuming you live in a city. Drive very carefully and see where you can find potholes, sand trash, weeds, etc. You might find that a lot of this information can't be easily updated without someone going through it everyday and even then how can someone record that data immediately. As for comfort. The most basic thing here is to angle your seat properly for comfort. Also raise or lower your seat so that your legs are almost straight when the either pedal is at its lowest point. This will ensure you don't put too much stress on your knees. Padded bike shorts can also do good for heavier riders, since the seat will be uncomfortable. In order to really improve your performance, I recommend riding 6 miles(3 miles in each direction if at that) and maybe me a small uphill somewhere along. Another thing, I find myself sometimes constantly shifting when I get tired. This is bad form and is teaching you bad techniques. Ideally you want to keep the pedaling to be equally fast on an entire flat road. Try to limit the number of times you shift on flat road. The cables in your bike will greatly appreciate this. Also, all of what I said above can be good advice certainly. But the best way to build yourself up is through riding. Every time you get on that bike you learn something, and that helps you reach new goals and it teaches you more. Ideally I would log my rides just so you can see how far you can go.