They have had their fair share of bad luck, and mostly bad finishing.
The issue is their shooting, not their general play. Unfortunately, their attackers can't shoot. They had 20 shots against Crystal Palace, but 17 were off target and only managed to score once, whilst Crystal Palace had 1 shot and scored.
They had 18 shots against us and hit the post 5 times.
Potter has coached them well, but without goalscorers, they won't win no matter how they play, so I don't see what there is to criticise him for.
Their results don't look great, but you have to consider the three losses have been against us, Chelsea, and Everton. They have drawn twice and won once against the three clubs you expect them to have a chance to beat this season.