I have only been hunting for two years myself and only Turkeys for one, so I have very little knowledge myself. But the few properties I hunt have enough birds that I was able to fill one of my two tags in the spring and the one in the fall.
As for time of day- I seen more turkeys in the morning (about 8:00) including a miss at about 20 yards, but both that I shot were in the afternoon one about 4:00 and the other just before 7:00. I did do a lot of scouting most of which just from the truck with a pair of binoculars (coffee too).
Type of call- I only used diaphragm calls on the advice of a older friend who has hunted for a long time, because it keeps your hands free and dose not require the movement of other types of calls. But it dose take a lot of practice. Youtube has some good instructional videos and then I practiced around the house (driving my wife insane) and in the truck on the way home from work or whenever I could.
Thanks to everyone else who responded, I thought some of the tips are good advice for myself, especially about the rain. On wet days I always stayed home 'cause I thought a sit would be fruitless, next year I will definitely try on a light rain day.