Advice from UToledo...
In 2018-2019 we had a brand new club of 9 total members, 4 of whom were active - the other 5 were to meet minimum university club sport requirements. Enthusiastic, willing to pay a $50 membership fee to get a few discs and help us out.
In 2019-2020 we finished out the school year with a total of 17 paid members, at a $100 membership fee.
So far in 2020-2021 we have 20 paid members, at a $100 membership fee.
I bring up the fee to just highlight that we didn't boost our membership by making being a member any cheaper.
The big key has been our early recruitment event - the Rocket Student Disc Golf Festival. Each of the past two years we've spent time at tables outside of the student union recruiting people to participate. Last year we had 8 total UT students participate, and 5 wound up joining the club, bringing along friends over the course of the school year. This year we had 20 total UT students participate, with only 1 of our returning members playing and 19 people we met just this semester or that day involved (due to Covid this just happened finally a week ago, final impact to be determined).
The event is run as simply as possible. We have a sponsorship relationship with Discraft so we buy up putters with our club stamp, and we give them out as player packs for a $5 buy in flex-start event, with their best of two rounds counting for the win. The club doesn't make any money off of the discs obviously, but the key is getting them into student hands (note: we don't sell the discs for that cheap price, this is a one time recruitment-event thing and we definitely lose money on the "giveaway" overall - the same putters will be sold at MSRP to help fundraise).
Even if you do something completely different - the key is getting engagement. Once you've got some engagement you can pull a person or two in, and from that you get some of their friends, and it balloons as long as you stay on it.
Another thing that helps: We use a Discord Server for all of our communications. It has been incredibly helpful. We have channels set up in Discord for: Looking for Round, Announcements, Disc Chat, Practice Report, Apparel Sizes, Social Media, etc. Non-members get 2 weeks with full access before we limit them to just the "Announcements" channel, so they get some time to chat with us get together for rounds, and so on to decide if we're a group they want to be a part of.
We probably have one of the faster growing programs in the country right now. We anticipate having 25-30 paid members by the end of this school year. The two pieces I shared here are probably the most important: get engagement (event), maintain engagement (chat server/channels).