Calls work, I have even had deer answer me. But the timing has to be just right, and how to determine that eludes me.
A everyone else has said, wind, lack of movement, and silence are key.
Story on calls:
I was hunting in green coveralls with a face mask, when I walked out on a rise.
Below me I spotted a doe, I ducked right away, but she saw me without question. I tipped my can call, as she might have a buck with her. She answered, exactly like the can call! Then proceeded into the fence row. I did the same and knelt down, with the crossbow up in front of me. She appeared fairly quickly and walked up to within 20 feet or so. I had no doe tag. She stomped her feet, and looked at me tilting her head this way and that, and eventually left, going up my tack where I had entered the fence row. I thought, I'd trip the call again, and see if there was a buck, so i did. ... The same doe came charging back the way she left, and we went through the same dance again.
As to camo, I have another story.
I was dressed in solid green work coveralls, with a face mask. I was moving from one spot to another, to get warm, when I spotted a good buck moving on an intersect path along a fence row.
There was nowhere I could find cover.
I was downwind, but just barely.
I knelt down out in the open, just up the drive a bit from where the fencerow met the road. The buck eventually came out, spotted me immediately, and, I think because I was green, and had the crossbow up in front of me, mistook me for some sort of weird deer. He cautiously came towards me!
At 20 yards or so, I fired. Found him 300yards away stone dead.
Another time, I was out in December, and just returned from lunch, I was using Fogduckers doghouse blind that day. I had no more than got in the blind, when I see this huge buck, at least a twelve point, at 300 yards out. He was eating, and grunting regular as clockwork. I tipped the can call that had worked so well on the doe in the story above, and he totally ignored it.
So, after a few seconds, I used my true talker, to imitate his grunt. His head shot up like I'd smacked him one, and he trotted into the fence row. Here, I had a problem, I was in a tent blind, and he was coming up the row behind me. He came out to where he could see the blind in thick cover, showed me his big white ass and was gone.
i have to date never had any luck rattling at all, and usually, I stay completely quiet. I think the motions you go through using calls etc, can give you away, so you best be well screened.
The best advice I can give, is to use all the techniques you can, but use them sparingly, use cover, use the wind, control your scent, and be so motionless you freeze your ass off. Then you will see deer.