Well for what it's worth, I drink real coffee black, no sugar.
The only way I can manage instant is, to use a good blend, preferably Kenco Colombian.
I put about 2 teaspoonfulls of cold water in a cup, add the instant coffee, stir it till dissolved, then add milk. I then top it up with boiling water.
Somebody once told me that you should never pour boiling water on powders coffee, just the powder/granules that is, as it makes it more bitter.