I could use some trolling advice/help

I'm still on my quest to catch my first Walleye, first anything trolling actually, and 11 hours on the lake yesterday without so much as a hit has me ready to scrap the idea of getting a bigger lake boat. I tried everything I've read to try yesterday, and fished from 60-85 FOW from the trench out of Walnut around to the lighthouse at Presque. Ran 2 retrosky's off downriggers (8# cabela fish shaped ball, and a 10# lead "finned" ball), trying depths from 25-down, crawler on a rig from 30 down to bottom bouncing (caught a mussel) and a spoon on a dipsy (again, caught a mussel when I stopped). I tried speeds from .5 - 3.5 mph, varied the distance from the ball from 40' to 8' I saw fish on the humminbird, and it even showed some coming up towards the bait (I always tried to put the lures above visible fish).

Finally stopped in 60 FOW out of Walnut at the end of the day and got a few perch and white bass until the rain came. Still have minnows in the bucket to find a use for.

Oh, line is all superbraid, with 10'-30' of floro leaders tied on.

I know it would probably be better to use more lines at once, but I have a hard time handling 3 since my wife gets seasick and isn't much help.

Man that blows. I havent fished for eyes in over a month. I wanna say the bite is slowing down. This year marked my 3rd year of walleye fishing, and I can honestly say that we're getting better at it. My first year I couldnt buy an eye. Sounds like you're doing alot of the rite things. It just takes some practice. Dont give up man. Next season can only get better for you. We only run 4 rods, and that can be too many sometimes with 3 of us fishin. ( 2 fishin and a driver ). I've tried various ways to troll for them, downriggers, spoons etc.. But I always go back to what has worked and that's Dipseys and crawler harnesses.