The first step is to understand what impacts your credit score. Then allow time and be patient as it's a long-term process. Building your credit score can take years.
You can see what’s currently impacting your score in your credit report. Log into ClearScore and go to Credit Health and see your report. You can learn more about insights impacting your score. If you don't see any insights on what's impacting your score in your report - check this article where you can take action to affect your score.
If you don’t have a credit score, check steps you can take to build your credit history.