im not a great player and im from low elo, so i dnt know hw much this will help u.
its probably bcuz u ward right in front of their eyes, dnt ward right in front of them, u r just giving them an info that that area is warded and thereby they could comeup with some plans, and when u ward keep tab of the minion wave, if its pushing towrds u then ward the side bush on their side, this will make sure there wont be any lane ganks and help u set up a top laner tp gank, and since ur pushed in, its hard for the opponent jungler to come by sides.
if the lane is getiing pushed towards the opponents, then u can ward safely without the opponent noticing and ward the side bush towards ur side, cuz the opponent top laner might tp onto the bush where u would hav no vision(if u didnt ward it) and they are already behind u
and ofc ur pink ward must be either in the tribush or in the drag pit(place it before letting the opponents know that u bought it), place it such that if they ever try to destroy it u can defend it and since ur supp main, try to ward deep in enemies jg( near the opponents' blue or red buff), this is even better than warding all 3 near ur lane, and take sweeping lens, and sweep out the obvious places, and u should be the one putting pressure by removing wards.
i rarely play bot lanes so these are the only things i could come up with now,ask a better player for more info
gl hf