Make sure you get it nice and hot with flux so the solder flows into the wire and doesn't sit on the top... if you a terminal on half hot dog style you souldnt see copper all the wire should me coatedt with solder, I always double solder mine I let the solder flow then cool and heat the top to put a nice cap over it at least that's what I do
I had some solder flow from the bottom of the terminal and fall on my foot, last time I ever soldered in my basement bare foot ........