Interview Stages
Some companies have a very weird interview process and I have been very fortunate to experience quite a few different ways of interviewing.
A lot of companies have the ususal 2 stage / 3 stage interview process which can be quite grueling and worrying. In my current job I had a normal 1st interview, but then had to do a presentation on my field and go into detail in regards to methods I would use etc.
The best thing to do in this situation is to remember that they wouldn’t have asked you back if they didn’t like you in the first place, so you have pretty much got the job already, but at the same time don’t be complacent because you don’t want to fall at the last hurdle.