It depends what you want to do with them as to how strict you want to be but I start as I mean to go on and I am pretty strict with mine. Probably the most important thing is that they get only individual walks and training until I'm happy their training is at the requisite level and that generally means when they're well over a year old. They get playtime with the other dogs every day but they don't go on walks with them (or very seldom, Caoimhe's been on 3 or 4 group walks and she's now 11 months) as I don't want them to get into the habit of free hunting and/or haring around with the other dogs when they're out and not paying attention to me. It's a lot to ask a puppy to ignore the other dogs buzzing around and focus on me so I don't put them (or me!) in the predicament.
With both Rodaidh and Caoimhe I bought them at just over 5 months old and all Ro could do at that age was sit and walk on a lead but by 11 months he was in his first field tests so there's no big rush to do everything when they're really tiny. Caoimhe was a bit more advanced at that age but she still really only had the very basics and everything's been built up since then. I like to start proper training as in hunting and retrieving at 5-6 months. Prior to that teaching them their name, recall and getting them focussing on me and building a really solid relationship with them are the main things I work on, I want them to be focussed on me and see me as the source of all interesting things. I teach them sit (and 'sit' means 'sit until you're told to move', few working people teach a separate stay command), down, introduce them to the lead and start on a bit of off lead heelwork, a 'look at me' command and I start to introduce the whistle and also expose them lightly to gunfire but that would be about it for the first few months.
I don't overdo the training at a young age, tbh it's more about things I don't do than things I do. I don't walk them with the other dogs; I don't play casual fetch with them, any and all retrieves are done properly; I don't play tug games; I don't let them get into the habit of carrying toys etc. around and not wanting to give them back, anything they pick up gets brought to me straight away (I do let them play with toys and chew on chewies though and to most pro gundog trainers this makes me 'soft'); I don't ever ever ever let them chase anything - no bird chasing, bunny chasing, cat chasing etc.; I don't let them go more than about 5-7 yards away from me when they're out and I don't ever let them take themselves off free hunting... It sounds harsh and it is I suppose but as I said it depends what you want to do with them, I trained Rodaidh to work on big driven shoots and to run in field tests and Caoimhe's training is even more intensive as she's got trialling potential and it's an unbelieveable amount of work.
This thread might be useful for you, I've done a bit of a training diary with Caoimhe, she came to me at 5 months so a bit older than your pup will be but it goes through the stages of what I've done with her, I actually have another instalment to put on it...
http://www.cockersonline.co.uk/discuss/index.php?topic=61489.0