Warding is one of the most basic of fundamentals in League of Legends, right up there with the ability to aim skill shots, farm minions, and smite Baron Nashor. Pro players will, on average, drop nearly 20 wards over the course of the game, and supports are liable to drop something closer to fifty. If you ask a seasoned player what the most important item in the item shop is, they'd tell you that it's the Control Ward, and even then only because Riot saw fit to remove the Sight Ward from the game.
Thus, knowing how to ward is an important skill. I'm not here to drop a ward map on you -- an easy google search can provide you with all the most common warding spots in the game -- but rather to help guide your mindset when you're placing a ward. There's a simple principle when deploying vision: the deeper you can put it in the enemy territory, the more information it will give you. As the purpose of warding is information, that's a pretty important truism to keep in mind whenever you feel like dropping a ward.
As an example, let us consider two possible ward locations that you could drop from the mid lane. Most mid laners are content with dropping a ward in or around the brush on either side of the lane. Such a ward will help ensure that you don't get ganked, as it will inform you if the jungler is in the area if they walk over it. Compare that to a ward in the Raptor brush or the brush on the other side of the wall from Wolves. A ward in either of those locations provides you with even more information, as it will tell you what side of the map the jungler is or isn't on. That information provides a much clearer picture of the state of the map as a whole than a simple ward in the brush will, at the cost of slightly less detailed information.
The risk is, of course, running into the enemy jungler along the way, but that happens a bit less often than one might expect -- unless the enemy jungler has made it their mission to screw you specifically. It's also not terribly common for most jungler to be able to solo kill a solo laner early on in the game anyways, as their resources have largely been expended fighting against the minions to the point that they can't really compete with a solo laner who likely outlevels them.
As the game moves on, the information you can gather changes from the position of the enemy jungler to the location of the entire enemy team. Deep wards help you spot enemy rotations, and they're absolutely vital to setting up any kind of split pushing situation. Seeing as 4-1 or 1-3-1 configurations are the default even in solo queue, it's almost certain to be a good investment of your time to get some vision to see if the enemy is collapsing on either you or a teammate.
League of Legends is a game of information just as much as it is a game about pushing your buttons as fast as possible. Maximize the information gap between you and the enemy team and your decisions will be smarter than theirs, meaning less deaths for you and more for them. If that doesn't sound like free LP, I don't know what does.