Read, translate and remember.
act − act$\mathbf{\text{or}}$
football − football$\mathbf{\text{er}}$
produce − produc$\mathbf{\text{er}}$
sing − sing$\mathbf{\text{er}}$
write − writ$\mathbf{\text{er}}$
manage − manag$\mathbf{\text{er}}$
work − work$\mathbf{\text{er}}$
art − art$\mathbf{\text{ist}}$
chemistry − chem$\mathbf{\text{ist}}$
piano − pian$\mathbf{\text{ist}}$
science − scient$\mathbf{\text{ist}}$
music − music$\mathbf{\text{ian}}$
politics − politic$\mathbf{\text{ian}}$
architecture − archit$\mathbf{\text{ect}}$
‘word + man’
business − business$\mathbf{\text{man}}$
police − police$\mathbf{\text{man}}$
show − show$\mathbf{\text{man}}$
sport − sports$\mathbf{\text{man}}$