I found when I was learning English something that really helped was to treat a conversation like a game of chess, think a few moves ahead, so for example if you are going to say "¿Como estas?" to someone, think of the possible answers that person might reply then formulate a response to that before he replies, so you keep doing this at least a couple of moves ahead, it sounds quite hard but your brain sort of gets used to it after a while, it's always better if you are the person formulating the conversation, meaning you are asking questions... to start with anyway, obviously you don't want it to be a one way conversation, you really need to listen and instead of trying to translate what people are saying to you just concentrate on simply understanding. Thinking too hard before you speak can get in the way of the conversation, sometimes asking a person to repeat what they have said a second time is better than taking 30 seconds to try and decipher what they've said.
I don't really have any exercises to help you with this but it might help to draw up a few mock up conversations in Spanish and study them so you make yourself some sort of "template" of questions and answers that you can have at the ready when you enter a conversation... I don't mean on paper, just memorize them. Start with only a few not to overload yourself, but the more practice you get the broader your "templates" will get.
I hope that is of help to you, it has definitely worked for me and now I find myself still automatically doing this, even though I don't need to, but it does help to steer conversations in the directions you want them to go.
All the best and good luck!