Difficulties with the Walk

My Renji tends to pull a lot and isnt content walking at slower paces. As soon as I get him through the door it's like his attention scatters to everyone and everything but me. He pulls me down the stairs sometimes often choking himself on his collar. My ideal walk would be having him beside or slightly behind me , especially since I often walk with friends, but im running out of ideas to achieve this and he seems to believe himself the leader even though I am constantly reinstating my dominance over him inside and outside.

Ive tried using treats as a motivator but outside he's simply too preoccupied with looking and sniffing to even care that I have his favorite snacks.

Ive had a bit more luck with a different technique but he just doesnt understand what I want from him I think. Every time he pulls I stop and ask him to sit. I line us up side by side and wait for him to calm down. As soon as he does I say "lets go" and we try again. This usually causes me to stop about 10 to 15 times a block but its slowly improving. I do the same with the stairs. After every flight I get him to stop so I can catch up although this doesnt stop him from charging down the stairs as soon as I give him the go ahead.

How can I teach him to keep pace with me? Any ideas?

[changed category ~mod.]