I am thinking about going this summer. Any tips on accommodations, restaurants and things to do besides theater?

This should help: http://www.welcometostratford.com/

There are lots of great B&Bs where you can stay - you can browse some of them here:
http://www.sabba.ca/

As for restaurants, are you looking for fine or casual dining? Any budget? There's quite a number of restaurants in all price ranges.

The Church restaurant might interest you: http://www.churchrestaurant.com/

I always start by saying that I own a B&B in Stratford so will not comment on the accommodations, except to say that we have something to fit every taste and every budget.

As a first timer, I would not try to plan too much. We have great shopping, lots of beautiful parkland to walk (or picnic in!) and of course the theatre. I always encourage guests to do one of the Stratford Festival tours- they are great compliments to you theatre experience. (Particularly the costume warehouse and backstage tours.)

We are spoiled in our restaurant selection here too... almost too many choices for me to list... is there a particular food style, ambiance or price point you are looking for?