Guidelines for queen trades in the middlegame

Are there some general guidelines on when it is good to go for a queen trade in the middlegame? I have made several inaccuracies on being up material, up a pawn or two, etc.. where I thought a queen trade would only help me realize my advantages but it botched it instead. I was just wondering if there were some rules of thumb on when it is a good idea to trade queens since I've never really heard of any. Thank you for your time. 

In general, the queen represents dynamic play (or at least the potential for it).

So (again, generally speaking) you should like to trade queens when you have static advantages to play against like pawn structure. Trading queens reduces your opponent's counter play and doesn't diminish your ability to exploit the static weaknesses.

If your play in the position is based more on dynamics, like they're behind in development, loose king, uncoordinated pieces, then in general you'll want to keep queens on. Trading would usually diminish your ability to exploit those elements.

Material is a static advantage, so usually trading queens is good, but remember to evaluate trades by looking at what's left on the board, not what's coming off. After any sort of trade (not just queens) if their remaining pieces are more active than yours it's usually not a good trade. Having much more active pieces can easily compensate being down a pawn or two.

Of course the reverse is also true -- if your pieces are much more active then go for it. For example even if 100% of your play is based on a mating attack, a queen trade can be good for you if all your other pieces are active, and the attack continues.

Oh, and a bit of advice about how to "go for" trades.

If you're just randomly moving your queen around attacking theirs, asking for trades, that usually just makes your position worse.

The way you trade pieces is to activate the piece you want to trade as much as you can. If you make it valuable enough, then your opponent will want to trade it off.

So for example with the queen, try to find a secure central post, or a square near their king. Generally speaking, if you're not at least infiltrating when you're the one offering the trade (when your queen attacks theirs), they wont even consider a trade (by infiltrate I mean a square on their half of the board).

Thank you for the great advice. I usually do try to activate my queen while offering a queen trade but the computer always tells me that allowing the queen trade was a bad idea; but if my opponent moves his queen (it happens a lot) I get a huge advantage. I wasn't really satisfied with this though since I allowed the possibility of my opponent neutralizing my advantage. Your point about dynamic vs static advantage is definitely the reason why as I haven't been logically deducting this and just thinking about having an advantage of some sort in the position would make the trade good and I start calculating but not accurately enough. Such a huge long-term drastic change in the game is hard to evaluate based on my calculating ability alone, but whether I have a static or dynamic advantage should be way easier to deduce. All the games that I'm referring to have been when I had a dynamic advantage. Thank you again! That was exactly what I was looking for, very helpful.