Always follow up after a networking meeting, coffee or interview.  You can easily follow up by email or a handwritten note can really stand out. If it is a networking meeting, let them know you are very grateful for their time as you know they are busy and that you appreciate all of the advice and help they provided.  If it was an interview, thank them for their time and let them know you are very excited to be considered for the position and very excited about the opportunity to work with a wonderful organization / company.