One good way to start or strengthen a professional relationship is just to share an article you think the person might enjoy.
Try to pick an article with meaty enough ideas that they might be a good conversation starter for the two of you. Needless to say, avoid hot button topics with people you don’t know very well (and maybe even people you do).
Nothing coming to mind? Try look through your favorite journals or feeds, or just Google a topic you think might be a common point of interest.
Once you’ve found an article, email a link to it and a short note explaining why you think that they’d enjoy it.