Structuring a referral program when you have a long sales process

My company's main growth channel is word of mouth. Our customers are eager to spread the word about us, and most new signups say they were referred. We want to encourage those referrals to go through our official referral program so (a) we can track the source of new signups accurately and (b) we can provide referrers with additional tools to be even more effective.

But almost no one uses our referral program. Right now, the deal is that if someone signs up through your referral link, they get an extra month on their free trial, and you get a free month when they pay (basically the classic Dropbox model).

Maybe the reason people aren't using it is that the reward isn't high enough or something like that, but I think the real issue is that no one signs up for a CRM (that's what we make) just by clicking a link. They normally spend weeks, months, or even years researching options, considering things, and getting all their ducks in a row. So the model of "click this referral link and sign up" just doesn't work here I don't think.

I'm trying to think up other ways we can offer tools and resources to our referrers that would be a better fit for the reality of a long sales cycle. I'm curious if anyone has had any luck with this type of thing.