My DF was really nervous about opening too many new credit cards too - he had 2 cash back cards, and a few store cards he had been talked into. I talked him into getting a Barclay Arrival Plus last year before our California vacation and we were able to use the $500 bonus towards our Universal tickets. When I wanted to get more into this, I showed him what the sign up bonuses could do for our honeymoon costs, and that helped change his mind - especially with the big wedding expenses, which we already had the cash for. I showed him how we might as well put everything on cards and then pay it off and get something out of it. I keep track of everything, because that's my strong suit, and I put important dates (like AMEX offers, minimum spend requirements) into a shared google calendar so he can see. I also remind him occasionally of bonus categories, because I remember those pretty well when I'm out and about. We use YNAB so we can easily check to make sure we stay on top of paying the bills to avoid interest/late fees.
We're going to WDW in September for 2.5 weeks for our wedding and honeymoon, and we've got 10 free nights (5 at the Dolphin and 3 at Four Points near Universal from SPG cards, and we're going to cover a night in Port Canaveral with Barclay points), free flights thanks to the CSR (going to book with points), and we each got a no fee Disney Visa for a $200 gift card bonus (each). We've opened 2 SPG AMEX cards, 2 Disney Visas, and I got the CSR. We're saving over $2k just on flights and hotel, because originally I was looking at renting DVC points for the entire time. My CSR travel credits (I got to double dip) covered around 2/3 total of our flights and 5 nights at Pop Century at the end of this month. And then with AMEX offers (though those aren't necessarily tied to a travel card with them) we've saved $420 on Disney gift cards, $160 on our phone bill, plus $50 on some other miscellaneous offers...
So we might end up paying $640-$1090 in annual fees, but we've gotten around $4700 in value at this point, so...