Avoid uphill traffic lights!
When I ride an old bike in traffic, I stop with the valves lifted, get off, and stand beside the bike. The driver of the car behind is usually amazed - so amazed that he/she won't run me over. When the light goes green, I push off with the valves lifted, drop the valves and jump on. For a Douglas, up hill would be in low gear, but on the flat or down hill I just do it in top.
Stopping with the engine running is OK, but not my style. If you do stop with the motor running and the bike in neutral, it's vital to paddle off and get moving before you jam the bike into gear - it's a bit rugged really.
When there is no traffic around, it's quite easy to paddle the bike off while astride in low gear, drop the valves, then away.
I'm not sure what other people do - perhaps TS riders can add their styles.
Cheers
Leon