General Tactics
Gogeta is a high power, high mixup character, with access to fast, devastating pressure, as well as the ability to control space on the entire screen. Although fairly slow in comparison to other beams, his 5S is his best tool for controlling space, and since it's a normal, you can vanish cancel on whiff to secure safety if necessary. Likewise, his midscreen and corner combos are very strong, leading to 40% minimum from almost any starter. Likewise, his invincible DP (214M) causes a same side wallbounce leading to easy to confirms and even kills if your opponent isn't careful, and his side switch invincible DP (214H) is good for starting combos in the corner if you're being pressure, leading to high damage and knockdowns, switching the momentum in your favor.
Team positioning
Point
Point Gogeta allows for his mixup tools to really shine. Access to two assists really opens the door for his pressure because his staggers are really bad. The only downside is that his assist is very strong and being point doesn't allow other characters to use it.
Mid
Mid Gogeta is arguably his best position. Having one assist still gives him strong mixups, but he is self-sufficient enough combo-wise to only use the one. It also allows your point character to take advantage of his assist.
Anchor
Anchor Gogeta isn't terrible either. He actually has some solo ToD's that aren't too difficult and it allows for both characters to use his assist. The problem lies in his solo pressure, because his normals besides 5L are all punishable.