When it comes to working with credit unions compared to banks, Denton had a few poignant observations. For instance, credit unions are more lenient on certain types of credit, she noted. A 20-year member who has worked at Alcoa, for example, may have a horrible credit history but a credit union will likely work something out, Denton said.

"There are some weird quirks about working with credit unions. They've really become more prevalent in indirect lending," Denton said. "As far as funding, some do it good and some do it bad. Everyone is different. As a dealer, one of my biggest fears is losing business from a credit union."

Denton said credit unions' reserves are smaller than banks and because they market directly to members, she has resigned to the possibility that she may never see a member again when it comes to financing.

The stakes have gotten higher for credit unions as banks and finance companies continue to compete aggressively for auto deals. Indeed, according to the CU Direct Survey of Lending Officers 2014, nearly 70% of credit union executives said increasing dealer network relationships was their top auto lending initiative this year to grow loans.

As for other ways to win dealerships' business, Denton suggested having someone around at the lending institution in the evening hours in case there are questions. Email and text messages are also critical forms of contact.

"I can't tell you how many hairs I've pulled out over the years at not having someone to talk to after hours," Denton said.

Lenders should also avoid dragging out the funding process. In the subprime market, funding can get held up for weeks, she's noticed. To speed things up, Denton suggested having as much as possible done upfront at the time of approval. It would also be helpful to have easy-to-understand contracts and letters of assignment, she said.

"I know there's different verbiage in these contracts and everyone wants to protect themselves legally. It's just very frustrating to contact someone and find out the next day you can't use the contracts. Call us up in the morning and say, 'Did you need anything from last night?'"

With the myriad regulatory and compliance changes within the auto lending sector, Denton said she understands the pressure some lenders face to ensure that their portfolios follow fair lending rules. Lenders who go that extra mile to educate dealers about updates through on-site workshops are always appreciated.

"Smaller lenders are saying, 'whew,' but I don't think anyone is immune. Everybody is still trying to figure out what's going on," Denton said. "But some of the smaller lenders are more agile with getting documents in place. I think because they're smaller, they feel they're a little bit more exposed."

Other tips? If lenders deviate beyond an average rate markup, be ready to explain what caused it, she said. And, one surefire way a lender can lose Denton's business is to get caught in the middle of a financing spider web.

"Sometimes, lenders will say 'we have this business for you,' and then I'll call them up and they'll say 'I can't help you … this came down from the top.' That can be a death knell of the relationship."

Denton advised lenders to get creative with their programs and expand existing ones. There's room for fresh approaches such as guaranteed buyback programs, she offered. Pinpoint which markets to serve – franchise or independent and subprime or prime – and if they're already serving these groups, be sure to understand all of the ramifications. She pointed out the subprime market continues to grow.

"One of the shortfalls in financing is working with the self-employed and small businesses. As a small business owner myself, I had to pay a ridiculously high interest rate. Decide if you want this type of business in your portfolio," she said.

Bringing it back to establishing a personal relationship, Denton said lenders who have a 60- or 90-second elevator speech ready can go far. Once the alliance is established, her top three criteria for lenders are response time, rates and funding.

Being straightforward and ethical also helps to establish trust, she noted. Staying in contact matters as well. Denton's lenders meet with her at least once a month.

"We do like treats," she admitted. "I started in this business when gifts and crazy stuff were popular. People had a lot of money in the 1990s. Now, cash gifts are a dangerous thing. There are some dishonest people out there."

To this day, lenders who make initial contact with a line card attached to a branded coffee mug, screen cleaner, breath mints or hand sanitizer, for example, puts that financial institution top of mind for Denton.

"It sits on my desk, I see it every day, I may call you," she added.

Denton also emphasized heradmiration for credit unions.

"I love my credit unions. I have a very a good friend who is a lender at a credit union that I've belonged to for 20 years. They do indirect and I send them a lot of car loans," she shared. "I've talked to him about this before: You have to strike a balance, have a conversation. There is room for balance and it all comes back to having that personal relationship."