If you’re introduced, shake hands as you’re introduced if possible (i.e. don’t climb over a table to get to them). Suit, shiny shoes, tie. Don’t bullshit about what you’ve done, NEVER badmouth previous employers or blame them for anything that might be considered your shortcomings. If you’ve been made redundant, be honest about it as there’s no stigma associated in in most eyes. If you can do some research on the company related to the role you’re interviewing for, do it but at the very least, have a reasonable idea of who they are, what they do, competitors etc.
Above all be confident, don’t get flustered and be yourself.