Same as always: treat them well, pay them fairly, don’t be a dick. It’s quite easy actually.
How about a hypothetical:
Take your current paycheck amount, now multiply it by 10. That's the pay offer from the other probably dickish company. If you last even just 1 year at dickish employer, you can take the next nine years off and still be ahead financially. If you last 2 years, you may be financially set and done working for the rest of your life.
Would you stay at your current employer?