The teenage years

Just recently laid-back and clumsy Archie has morphed into a pain in the butt!

He still sits, lies down and even comes back on command but he has become quite aggressive towards other dogs - even his little buddy Tobey. One minute they are happily playing and the next it has turned nasty and I have to intervene. There is also the issue of him barking at anything and everything - I "sssshhh" him, he stops then 2 minutes later off he goes again :eek:

As he has only just turned one I am pretty sure its "just a phase" but do you have any tips on how to make it easier for everyone to live through