I have taught Ramsey the "look" command and I use it often on our walks.

Now he looks at me so often without the command I don't know if I should continue marking/rewarding every time?

I wouldn't mark it it if it wasn't commanded.
It's good that he understands he needs to focus on you and stay engaged. Now is the time to proof it and start working on duration.

I would continue to encourage the looking (Good Job! Good Boy! etc), but I wouldn't feel the need to mark and reward every time, unless in a training session.

What I would start working on, is building duration, working it into a front sit/stationary heel/down/moving heel positions and slowly introducing distraction (not all at the same time of course). Once that is done, I would work this command in any place I could think of and build up the dogs ability to commit to you even in busy, distracting situations.

This may sound stupid, but, how long( duration) am I aiming for? Are we talking 10 minutes, 5 minutes etc.?

Good luck on a 5 minute look!

You're looking for seconds, just one or two at first; you then build on that. Your goal is not to have him stare at you indefinitely. It is to have him able to focus on you as he completes an exercise or needs to break from a distraction.

I most commonly use the look for getting the dog to focus for OB. If I give a ready to start OB and my dog looks away, I'll give a look command, and she redirects her focus to me. It is a reminder that we are working and she needs to stay engaged.

 Quote: Carol Blumlein

This may sound stupid, but, how long( duration) am I aiming for? Are we talking 10 minutes, 5 minutes etc.?

I think this depends on what your training goals are.

For example:

For my "pet" dogs, I never require a focus for longer than 5 minutes, and that is pretty long once you are standing there waiting for someone with 17 out of control dogs, all on haltis (with no back-up), all are dog aggressive, and wait for them to pass by.

So I train for 5 SOLID minutes with these dogs in a stationary heel or front sit position. And this is the position I will put them in when we are working under distraction as well. When they were young it started with seconds, and worked up to a minute, then two, then 3, then 5. THEN you have to also add in distractions, starting from low to high, then take away the food and do the proofing steps back at sqaure one - so it is a process and some days will be better than others.

For my competition dogs, I want them to hold a 15 - 20 minute SOLID focus if we are stationary and I want a commited "in motion" focus, but they can (and should) also make quick glances to look for whats coming and where they are walking...LOL And on the other side of the coin, I also taught a "mark" command. So I can indicate to "mark" an object or person, and the dog will not focus on me anymore, but remain in the heel position while focusing on the person/object.

The competion focus was also started the same way, but I just took it further with the duration and distraction.

This command will and SHOULD take time when done correctly. If you rush your foundation and cut corners, eventually the house will fall. So take the time to get it right and work on the little stuff. It wil be completely worth it in the end.

Thanks for the answers. I can see it getting better as he grows up. It definitely takes time.

Yes, in time he will start to look at you whenever he's engaged, without a command. Later, as he becomes more advanced in training, he will look you in the eyes whenever he's engaged and waiting for the next OB command, and that will become an effective gauge for his engagement.