Well, from memory, the first and clearest no-no was a daily high dose of vitamin C - Dh was taking Berocca every day, and since cutting it out has seen a huge improvement. Who knew?
I also remember strawberries can be inflammatory. And we now add flaxseed to our porridge, it has loads of beneficial properties including being anti-inflammatory.
Less red meat and alcohol of course 
, and lots more fish, esp oily fish, in our diet.
Those are the main habits we've adopted.
The most eye-opening fact I found when researching arthritis was that the body's fat cells actually produce an inflammatory chemical. So as well as putting more strain on my joints by being overweight, my lovely fat cells are actually creating inflammation. 
This was the single most persuasive fact that has motivated me to get moving on my weight loss journey again. And running is the best fat burning activity I can think of!