How do you maintain/build your network as a professional?

After searching WSO, I wasn't able to find a post specific to what I'm asking. One of my old bosses had an excel very similar to this and it's something I am beginning to utilize: https://www.wallstreetoasis.com/blog/keep-in-touc…
However, most of the networking posts on here seem to be geared towards undergrads for internships/FT. So my question is for those of you that have gotten your feet wet and feel confident in your networking ability for the purposes of maintaining your professional network, and adding more to it.

An in-depth response would probably be helpful to a lot of younger users, so @ anyone you feel is a power networker. Needless to say, any quick tips and tricks would be appreciated.

Maintaining:
Do you utilize a similar excel file, or have something different? When do you typically add someone to that list, and what do you think differentiates the way you monitor/use yours?

What's in your networking 'toolbox'? i.e what do you do to actually maintain the connections, and how often are you doing these? e.g Give them a phone call or a quick checkup text/email? Or do you just try to make an effort to grab a coffee? Take a group of clients on a fishing trip or something once a year?

This may be reserved for more personal connections, but do you do anything along the lines of birthday gifts or holiday wishes? What's your method here?

Anything else related to maintaining your network would be great.

Building:
As mentioned before, how and when do you add someone to that excel rolodex (assuming that you don't just wait for new connections to come to you) what do you personally do to actively build your network? Such as attending industry conferences, going to happy hours in your city, joining organizations in your area/nationally, becoming a club member somewhere, etc.

When attending something similar to the above, obviously the setting matters, but what is your overall mental game plan at a broad level when you are speaking to people you'd like to add to your network?