If you wish to establish a new tonal centre, a good method is to precede it with its dominant chord. Strengthen it even further by preceding the dominant seventh with ITS dominant. This is referred to as a string of secondary dominants.
Example. In C major.
C, Am7, Dm7, G. Probably no modulation. The next chord is likely to be C.
C, Am7, D7, G. Maybe a modulation. G is preceded by its dominant 7th chord. The music could proceed with G being treated as tonic.
C, A7, D7, G. More chance again of it being a modulation, rather than 'just visiting'.
In all cases, what happens next is more important than the chords leading up to the G chord. OK, we've got there. But are we just passing through, are we pitching a tent, are we building a house.. ? Is a passing visit a 'Modulation'? Maybe. It's only a word. Between 'just passing through' and 'settling down for a long stay' are many degrees.