I cant tell ya when the season starts in Ia, but I live in N. Mo not far from the Ia line and our season starts in the neighborhood of the middle of the month, during the beginning of the season I like to hunt the birds on the roost hoping the ol tom isnt henned up already, if he is, good luck with that.
if im not having any luck by 0830 i usually back out and go back to the truck and have some coffee and breakfast then hit them again around 1030 or 1100 after the hens leave the toms, if you can try to find out where the toms struttin zones are at and hit those areas.
if its later in the season and the ol boys are gettin call wise i dont usually go out till 1000 or so and hunt the method i just mentioned.
this may not be the best way but its worked for me, i try my best not to over call, just enuff to get a tom to talk and get a location on him then sneak in for the attack:D
as i said this method might not be best but hopefully it will give ya some ideas anyway, good luck with your hunt and any day in the woods or on the lake is better than any day at work wether you fill a tag or livewell or not