To help with basic boat handling:
1. The boat will only steer when you have power on, in the forward direction. Doesn't have to be much power, but it does have to be forwards. In tight spots, it pays to come in as slowly as possible and then use quick bursts of power with the rudder fully over to steer, using reverse to slow down inbetween if necessary. With practice it's possible to get the boat turning and let it continue the turn whilst putting it in reverse. "Pumping" the rudder can sometimes help you to turn more sharply.
2. When steering, the boat will pivot roughly around the middle. It's therefore essential to allow space for both the pointy end and blunt end to swing when turning.
3. High winds can be a real nuisance, in general slightly more power is often the answer, even though it's more inuitive to back off.
4. Contrary to popular advice, boating ISN'T a contact sport. However it's a very inexact game and the only way to learn is to start. No-one minds if you're trying your best to avoid a collision but end up nudging another boat gently becuase you've run out of options / luck / skill. Just try to do it as slowly as possible (i.e. while making considerable effort not to make contact at all) and say sorry if necessary. There's nothing more British than everyone saying sorry to each other over an event that was pure random bad luck.
5. Tea should be used for bribery purposes prior to 12 noon, beer thereafter.