Whilst I agree with Slag that it works very well with Specsavers, I do like words pronounced as they should be. It's all to do with the characters. You only have to listen to the likes of Mitchell and Webb, Alan Partridge and Frasier to see that the written word with no contractions can be very funny. But for guys like Joey from Friends contractions are vital and he would be ill at ease speaking correctly.
A good tip, I think, is to join conversations already in progress. Instead of the
'Hi'
'Hi. How are you?'
'Okay, how are you?'
Skip it and start with the likes of
'So what did you say?'
'What could I say?'
etc
Start late, finish early.
