There are 5 main factors that make up credit score: payment history, credit utilization, length of credit history, new credit, and credit mix. First of all, you should always monitor your payments so that to be able to cope with all them. Secondly, your total outstanding debt shouldn’t exceed 30% of your available credit. Next, if your credit history is short, adding too many new cards can reduce the average age of your credit accounts, which can also impact your credit score. Also note that your accounts had better be of different types. Take care of having mix of credit cards, personal loans, etc. If you follow all these rules keeping your balances in good standing, your score won’t be irreversibly affected.
In case you have never used a credit card, we would recommend you start with secured credit cards. These cards require a security deposit paid upfront. A secured credit card is a good way to build your credit history as it reports the account activity to major credit bureaus. You just need not to miss payments and pay off your balance. After that, getting approval for an unsecured card will be much easier.