I can honestly tell you now, finding sponsors who donate funding is extremely difficult. Actually the only one I have is my wife's business
She pays my entry fees from her business account and calls it advertising since I have her logo on my shirt and boat.
On the product side, don't solicit sponsorship from any company you don't use and believe in. All my tackle sponsors are products I believe in and use. I won't put a name on my "equipment" (boat, truck, shirt, etc) if I don't believe in it. Some anglers just think "hey it's a sponsor, I'll take it" but that's not the best route to take.