Speaking as a team lead, the most important thing is to know what your expected role is - are you a manager? Are you in charge? What does your boss expect of you, and what does he expect of your peers?
You succeed when your team succeeds... if they don't, then you don't.
In my case, I don't have any authority other than influence. That's ok, it also takes a lot of responsibility off my plate.
If you have authority over people, know that you can tell them what to do if you have to, but if you reach the point where that's all you can do, you've failed.
Knowing what's expected of you by whom is important regardless of your role. And also team success over personal success -- you have to be in some petty backstabbing nonsense for those things to not be tightly related.
I have a Lead title at work, but like you I don't have any authority over anyone. So I don't really have any advice for the OP, as it seems what "lead" means varies so much from company to company, and to me as soon as you get in the business of authority you really need to start thinking about management, not tech, to which I can only suggest read Deming.
I think my ideal model for 'tech lead' is something like how (I've heard, could not actually be the case) Bryan Cantrill at Joyent operated. Even when he was VP Eng, and later CTO, he still was involved in code, and generally engineers there both "led and were led" without very hard cut roles on that axis.
You succeed when your team succeeds... if they don't, then you don't.
In my case, I don't have any authority other than influence. That's ok, it also takes a lot of responsibility off my plate.
If you have authority over people, know that you can tell them what to do if you have to, but if you reach the point where that's all you can do, you've failed.