My puppy golden retriever is very friendly and no problem apart from he follows me everywhere!  When I go out in the day he is locked in a room by a stairgate, and is fine then.  However I cannot lock him out there in the day without him barking continously! And I can't leave him barking because then the neighbours complain, hence I have to return to him, which is obviously teaching him bad habits of barking to get what he wants. I also don't want him following me upstairs etc, to prevent HD.  And he needs to be left with others when I go on holiday, etc in the summer, so I need the behaviour to start changing now.  He's four and a half months now, and i've had him since 6wks.  He was kept in a crate until about 3 months, but now has a room out the back.  I also have a border collie, so it is not as if he is lonely, but is just obsessed with me!  I just wondered if anyone had any advice because I can see this becoming a big problem in the future, as he only wants me.  I live with my mum and my brother who are always working, so he relies on me for everything, and hasnt bonded with the rest of the family.  I was going to start spraying him with water first every time he barked when I walked upstairs, etc, but has anyone else got any suggestions.  He already goes to obedience training classes.
Sorry for the long essay! Thanks in advance!

Can you have a word with your neighbours (and maybe the family too)? Explain that you're trying to train him not to bark for everything he wants and that this is going to mean there may be short periods of barking while he learns - but it won't last........  then continue to train him to be alone by NOT returning when he barks, but when he's quiet and praising him.

Can you not put baby gates up to prevent access to rooms/stairs? 

Shape the absence of barking by only returning the nano second he is quiet and treat, extend the absences and build.  Also when you do leave him give him something he never gets at any other time like a stuffed kong.

I think spraying him with water is unkind in this particular circumstance; you need to train your dog to be alone otherwise he will not grow into a competent and confident adult and be able to cope with your absence and may develope separation anxiety which is crippling not only for the dog but also the owner!