Once you get to the point that bots are easy, move to PvP. Do it before you can handle bots easily, and you're more likely to attract harassment from inconsiderate players. You definitely want to make the transition sooner than later, though. PvP is a massively different environment, and you'll want to learn how to counter real people's plays.
Wards are for vision. You know how when the enemy runs a little too far, you can't see them? If they're in range of a ward, you'll still see them. In bot games, they're almost worthless. Against people, they're necessary. Players go through the jungle to sneak up and kill you unexpectedly. Placing wards in there will give you early warning and let you plan accordingly. One thing you need to keep in mind is that the wards won't see through walls or into bushes. To see into a bush, you need to put the ward directly into it. It'll still provide coverage to any line-of-sight areas within its range outside of the bush.