What are the things you must do in the order to get full credit for the day?

You need to make at least the minimum payment each month, even during an interest-free period. Set up a Direct Debit for the full monthly balance, or for as much as you can afford to repay. This will mean you don’t miss a payment, which could lead to unwanted charges and the loss of any introductory rate. Missing payments could also damage your credit rating.
You’ll have a credit assessment by the card provider when you apply, which will usually include checking your credit reference file. A good credit rating will improve your chances of a successful credit application. It could also give you access to cards offering the lowest interest rates and/or promotional offers.
You need to be at least 18 to apply for a credit card. With some cards the minimum age is 21.