Firstly, nothing wrong with, if you send to the interviewers or at least to the principal interviewer a short mail after the interview and thanking again for the interviews and mentioning that you would be looking forward to receiving their answer. This should be done, however, in a short and nonhyperbolized manner. Secondly, and this is very relevant in case you had not gotten the job, you should contact the company to ask for a personal and detailed feedback of your interview and about your performance. This is very helpful in order to improve for the next interview. In addition, you should reflect on the previous interviews and go through it step by step. Reviewing what went well and not so well. Focus on the improvement areas and write down specific action steps on how to better prepare and execute in the future.