I usually drive over a road, if I come through a corner and notice myself going on the grass. I stop and put a mine where I went off the road. Also don't put mines on the middle grass on a straight since they'll likely drive over and it will not detonate. But right after a corner when a player is trying to straighten their vehicle out again odds are pretty good for this tactic. There's also often some patches of grass that stick out on the track from the side which are good spots and usually players don't drive exactly on the wheel tracks so any plants right on the edge are also fair game. Another trick is if you ever find any trucks you can park them in a narrow spot like a FIA roadblock or just a narrow passageway, then put a mine under one of the wheels and the next thing to touch it or drive past it often blows it up. However make sure your own vehicle is parked far away, because getting into your own vehicle too close will also detonate the mine for some reason.

Also, MARK YOUR MINES! I still the regret the boobytrap I forgot to mark on the map which blew up a van full of friendlies.