Depending on where you are and what element you have you will get a boost. For example if it is windy wind users can get an attack boost and depending on the skill a certain add on to it. The environment can be from weather, where you are, or from people (the people one is a maybe). For weather it is snow-ice rain-water windy-wind Heat-fire sunny-light thunderstorm-lightning cloudy-cloud night-darkness. For where you are volcano-magma frozen area-ice dark place-darkness on earth-earth(as in ground made of dirt/rock) in forest-nature sea/pool-water. From people this one is kinda like a tag team thing so i'm just going to give a few examples. For Wind: One user sending out a gust then another sending a gust hitting the first one making it bigger and stronger.
it will be like that for most of the tag team attacks. For element combination tag team attacks it would be like Acid+Wind to make acid air (poison) or Lightning+water the lightning would have a bigger range.
I want to post more but first I want to get the idea out and see if it's good enough to be added.