Jeans are just about the worst cycling attire. They are heavy, stiff and have really thick seams. Polycotton hiking style pants/shorts are more practical if you want a street look.
Padded cycling shorts are useful on longer rides (over 1 hr). Wear nothing beneath them and always use a clean pair. You can use them as padded underwear beneath baggy shorts or pants.
Wicking shirts are more useful in cold weather to prevent you chilling out. In hot, humid conditions they can also be more comfortable than cotton. Some people say never use cotton but Ive done plenty of miles in T shirts.
Gloves will protect your hands in a fall and will alleviate vibrations.
Dress for the weather. If it is cool or cold, add some clothes. There are some people who insist on wearing shorts and T shirt on a bike whatever the conditions. Brrrrr.