I know that learning Polish verb conjugation can be tricky at times, so here is a trick you can use to be understood.
Use :
subject + the infinitive
While this isn't too common in our regular conversations, it can be very helpful when you forget how to conjugate verbs Polish.
e.g.
Ja robić zakupy
Ty robić zakupy
On/Ona/Ono robić zakupy
My robić zakupy
Wy robić zakupy
Oni/One robić zakupy
You can do this with every single Polish verb.
If you want to put emphasis on when is the action being done, just use the right word.
Wczoraj - Yesterday
Dzisiaj - Today
Jutro - Tomorrow
Teraz - now / right now
Ja jutro robić zakupy
Ty teraz robić zakupy
On dzisiaj robić zakupy
Ona wczoraj robić zakupy