This tip should almost be at the beginning of the list,
but it is fine here.
Simple tip: Get one, and don't forget it.
As far as I know, no state offers a 'ice fishing
only' fishing license, and that means that your license
will only be good until the start of the next fishing
season, which is often April 1st of the following year.
(Some may be March 1st, or some other date.) If you are
going early in the ice fishing season, then you really
don't need to worry when the fishing license expires,
but later in the season you will need to be aware of the
expiration date of your license.
The important thing is that you need to have a
current license. Now some states will allow an
electronic copy on your cell phone, but just to be sure,
make sure you have an official license in your
possession. I often print out a really tiny version (the
size of a credit card) and use that. If they have any
questions, certainly the electronic version on your
phone will work.
Next up: Proper Identification