How to go from informational interview to casual conversation?

Hey WSO,

I've been heating up my networking efforts lately and have gotten to talk to a few alumni at some firms I'm interested in. I think I'm doing a good job at getting the other person to discuss their background, their work experience, their job, etc. I think I'm doing a terrible job at turning the conversation around and really building a bond with them. I've tried searching for this and have seen a lot of the popular info interview 'guides' posted all over WSO, but I can't quite find an answer to this.

If it helps, the general structure of my phone calls have been- general intro --> their background/career/job --> 'advice' questions --> awkward questions I pull out of my ass on the spot to keep it going --> "Well, don't want to take up much more of you time, this has been really great...etc." My thank you email after is almost always well received and replied to 'with great to talk to you and keep in touch/feel free to ask questions/etc.'.

I know it's kind of lame to be asking this, but do you guys have any tricks or tips that have helped you in the past? Thanks!

(PS- do you guys typically add an alum you reached out to/had a phone call with on linkedin afterwards?)