One important thing that should be considered while you are in Makkah is to make sure you are truly facing the Ka'bah while praying. Sometimes due to crowd, you may not find a place where the saff is marked on the floor. I have seen people praying towards the pillars many times, even though the saff marking on the floor was clearly visible. Sometimes the carpet is not propery aligned according to the saff marking. This is very dangerous for those who don't know.
The carpets below the mukabbir (where the Imam leads in Taraweeh) are NOT aligned properly. Most of them face straight in line with the Imam's musalla and when you stand on them, you go slightly to right or left of the Ka'bah. Care should be taken always. Only the marking on the floor (marble & granite) is correct.