If you have to wait for references, you should be able to take care of that in a day or two, and keep the candidate apprised daily. Next, find out what things are worrying your job candidates. In the US, a common problem is getting work visas for people from other countries. Get a great immigration lawyer and pay all expenses. In some markets, especially Silicon Valley and New York City, the housing situation is insane.
Apartments are absurdly expensive and real estate brokers are sharks.
This worries people. All these are things you can help with by being creative. They're probably used to 6 weeks a year of paid vacations. Many people who like to travel or spend long weeks at the beach with their family would be happy to get more vacation in exchange for lower base salary, and they'll be more productive to boot. It's worth about 50 cents.