[djf]

I did that for one express purpose once, although not Mercury (which I have never spotted).
A few years back, Venus was totally stunning right after sunset. So I went each day to the same place, earlier each night, with some telephone poles and wires in the foreground. Finally, after about five days, it worked. I saw it in the sky, very faint. Before sunset.

[RightWhale]

You saw Mercury? Or Venus? Mercury is bright enough, but it is so close to the sun at best that there is still twilight when you see the planet. There are only a few minutes between when you can make out the planet in twilight and when it sets.