Hello @coruscate, to have contact with people who talk spanish is a good way. Travel to Spain or latin america is a wonderful experience too, because you have to talk in spanish the majority of time as you did in Mexico.
A cheaper way I recomend you is to watch tv programs in spanish, these help you to develop your listening comprenhension. It is the same recomendation that is given to us when we intent to improve our english level. A big hug.