pattern matching is mad tricky, the most obvious factor is colour, choose patterns that go well together in terms of colour and it will probably look great (that doesn't necessarily mean matching), easier said than done but I do feel like people often give colour way too little attention in outfits in general
the more difficult thing is to make it look effortless, which is really important for pattern matching imo, that obviously comes down to styling, what kind of garments you are wearing, what kind of person you are. clashing colours and print styles can be a good way to look effortless, or like you are trying way too hard
dries ss14 looks amazing on the catwalk but a lot of the looks would be extremely hard to pull off on the street, I think you have to think very carefully about what message matching certain patterns sends about you and whether that matches your personality, for me it has to be effortless and a part of that is not worrying about it too much or taking an artificial route to 'understanding' it through rules. remember clothing is much more about personality than anything else
I know that we struggle with it a bit at TEF and haven't really styled looks this season but gone for more individual pieces but it's definitely got amazing potential and is quite unexplored in general
I leave you with this

thank you dries our lord and saviour