Understand what are the things that you should stop doing, and what are the new things that you should start doing. What made you a great contributor and put you in a position to be promoted is not going to necessarily make you a successful tech lead going forward. You need to start optimizing your work around different metrics now. How much you produce with your own hands becomes almost irrelevant, and how much your team produces as a whole, and how quickly people on your team grow becomes paramount. Another aspect is that you should be managing up and sideways, be a voice and an ambassador for your team within your engineering organization. Be on the lookout for what is going on and provide air cover for people on your team.