Is there a distinction between 怎样 (zěnyàng) and 怎么样 (zěnmeyàng)?
They are completely interchangeable. 

I would probably say their effects are a very little bit different, (which people indeed wouldn't care most of time). 

怎样做 vs 怎么样做， the longer version(the latter) sounds like it might engage a bit more procedures or processes than the shorter version(the former). 

Again, that's just an effect, which couldn't be even a matter in practice.