I wanted to give a mention about the Celtic Cross spread (probably the most used tarot spread). I was taught to lay out the cards as in the picture below, but I have discovered during my teaching that this isn't how everyone lays out the cards. Indeed, there appear to be a number of ways that people lay out the Celtic Cross spread. The most frequent difference I've found is that cards 5 and 6 are reversed (meaning that card 5 is where card 6 is and vice versa). I have also found that in some instances, cards 3 and 4 (as below) are read in a different order meaning that their positions are relating to different aspects.
This can obviously cause confusion if you're trying to learn how to read the cards; I would say though that you should do what feels comfortable. I will always read this spread in the way that I've read it up until now (as pictured below - I should add, that's not my hand in the picture, it's just a picture I found online!) and indeed it's perfectly okay for you to even make up new spreads to suit you. As long as you know what the positions are and what they mean to you, that's fine.
For me, card 5 (as below) is to represent the immediate past and card 6 the immediate future. If you read them with card 6 being read as card 5 etc, I really don't think it matters. What matters is to be confident about the way that YOU read this spread and about your own practice.
Do let me know what order you lay out the Celtic Cross spread!
