I firmly believe one of the most critical parts of being senior or lead is availibility to the junior people. Seniors and leads often have tasks that only they have the rights to do (we don't give juniors write rights to staging and prod for instance). Plus a significant part of your job is to mentor the junior people which means answering questions not ignoring them. The more senior you are the more likely it is that you will be interrupted by others who need something from you. You need to give up that "do not disturb" sign and learn to work with interruptions.
Listening is important.
Please and thank you are important and cost nothing.
Don't expect more than you are willing to give. If you want me to work til 3 am, you had better be there beside me working too. Nothing is more discouraging than working for someone who leaves on time every day immediately after giving you a task that needs to be done by 7 am.
Be fair. Don't play favorites (especially don't play favorites by giving your girlfriend or boyfriend the best stuff). Treat all employees with respect (even people you personally don't like).
Be decisive. Don't leave decisions hanging out so that no one can progress or worse change them every five minutes.
Stand up for your people. You won't win them all but people will walk through fire for someone who supports them up the chain.
Be willing to be the bad guy when necessary. One bad apple can destroy a dev team, don't hold on to that person because you don't want to confront their bad behavior (this applies more for leads and offcial supervisors). When you have bad news, tell the team, don't keep it a secret (they will find out eventually and then they are mad about both the bad news and the secret keeping). You are not there to be popular but to get the job done. Anyone in a management or quasi-managment position has to be willing to be unpopular.
Learn how to sell ideas to higher ups and teach these skills to your devs.
Understand the importance of the business domain and become expert on it as well as programming.