Show enthusiasm! Vets and nurses are very busy but they will make an effort if you are seen to be doing the same - whether that is actively observing/listening or making tea/cleaning everything is appreciated.
Don't be afraid to ask questions - everyone within the practice was at your stage at some point and so long as it isn't an inappropriate time (infront of clients, in an emergency etc) they will not have a problem answering them. Once you get a feel for the practice there may be some hobs such as changing water, mopping, laundry etc that you can just get on with everyday - this will show very favourably
Some practices can be cliquey but stick at it, even if one is off putting it does not mean they are all that way