My suggestions for In-N-Out:
1) Secret menu -- Just Google it.
2) Grilled cheese for those who don't like hamburgers
3) Two by two, animal style, no special sauce, add hot peppers (for those that do like hamburgers and onions.)
4) Fries well done -- It is an experience. That's all I'm going to say.
5) Milkshakes are meh and super fatty. I usually get the strawberry lemonade.
I hope that helps.
And why three stars, you may ask? It's a regular old burger place, which makes it "A-OK" in my book. If In-N-Out offered a vegetarian burger and/or better fries, then they would be in the 4-5 star range. Alas, In-N-Out does not.