I have been using my American Express credit card for 24 months with a clean repayment history. How can I request a credit limit increase, and what factors does the bank consider?

I've owned 4 cards over the last 7 years. The biggest lesson: a card that fits your spend pattern beats the 'most rewarding' card on paper. A 5% cashback card you actually use daily will give you 10x more value than a 10% card you use once a month.