Once you are approved, be sure to keep good records.
Absolutely true, and excellent advice. KA4GFY is obviously very good at what he does.
Your club treasurer needs to be held to task on record keeping.
Although they don't bother with little bitty ham radio clubs very much, an audit is always a possibility, even if the chance is remote.
And if you are audited, you'd better have records.
An audit isn't anything to be scared of, especially if you have records that support your assertion made on the 990 form.
Basically, they're just checking to make sure everything is on the "up and up".
Also, it's a good idea to have an annual internal financial audit written into your club's by-laws.
It doesn't have to be fancy, but having another set of eyes that aren't your treasurer's look over the books, it sound management practice.
It's also a good idea to retain a written record of such an audit. Finding records like that put a real auditor at ease pretty quickly.
Good luck with your club!