I have a small saddle bag to carry a spare tube, patch kit, tire levers(2), allen wrenches, mini chain tool, spare cash and my cellphone(ancient Juke that is tiny). A rear blinky light that clips to the end of the saddle bag.

A pump that is held by a clip on the bottle cage bosses. I don't recommend the tiny ones, they just don't pump up high enough. Other people swear by CO2 pumps but I kept forgetting to bring the extra cartridges. There are manual pumps that will also use CO2 cartridges; best of both worlds.

I had a Giro helmet and thought it fit me until I tried a Bell. The Bell fit my round head better; the Giro is for more oval heads I reckon. Best to try them on before buying.

Stuff some food in your jersey pockets and with the stuff mentioned above you're ready to ride most anywhere.