I train gun dogs and have no experience of collies but at 6 mths we would always look at training/walking individually, building that bond, making sure the dog works with YOU learning, not just copying others. It is a slow and steady job and as doganjo previously said, 10 mins sessions. Repetitive stuff, very basic but drilling it in and always actively praising good and making sure that the wrong stuff is stopped dead in its tracks. We try not to let the mistakes occur in the first place, setting the dog up to always succeed. Little by little.
Quite frustrating most of the time, you always feel like you want them to do more but we find if we take it steady we don't end up having to correct later on. We often see young dogs that have been pushed too fast, and they are good up to about 18 months then they just lose it, especially if they are put on game too soon. Their heads just blow.