So thus far, from what I have seen in-game and while reading all the whining on the forums, I am the only person in the entire world who can use Varus effectively. Yeah, I know that's not actually true, but why are GOOD Varus players so few and far between? You have an amazing champ on your hands and you don't even know how to utilize him properly. I have played over 10 games with Varus so far, and have been in a negative K/D score once. Every other Varus I've seen, either on my team or the enemy's, has been stomped on by everyone for either making stupid mistakes or not playing Varus as he is intended.
So I thought I would give my top 10 tips to help out all the Varus players out there.
1.) Charge your Q to its fullest, unless they're up in yo grill. Don't worry, they won't be able to escape, the ability's god-like range ensures that. Unless you are terrible at skillshots, you'll be able to hit them pretty nicely.
2.) His W is there for a reason. Max it second, after your Q. Every time someone says his W is useless I cringe on the inside. Stack 3 Blight on someone, hit them with a full-charged Q and you'll see how useless it is, especially against a squishy carry. 15% of their maximum health in magic damage IN ADDITION to the physical damage from the Q itself. It hurts, people. A lot.
3.) Do not use his E as an offensive ability. Save your mana. Do not harass or shoot it into a teamfight. Use it when escaping, or to help a teammate escape. If you wish you can use it to proc Blight on multiple targets, but this isn't recommended, as the same effect can be reached with a well-placed Q.
4.) Don't over-extend, you have range. Varus' Q supplies you with enough range to stay away from the tower while still being able to poke at tower-huggers and remove them from the premesis. You don't want to be ganked as Varus. Without a sufficient CC it will be very difficult to escape without some work and a blown flash.
5.) His Ult is a snare. Use it. Every time you're being chased by multiple enemies, every time you're trying to track down en elusive foe, every time someone's trying to take baron and you can screw over their tank, pop your ult. You'd be surprised how amazingly useful it is, and how often it will save your life or land you a kill.
6.) In teamfights, target their carry and take them out. Varus is such an amazing anti-carry in teamfights. Once things get heated, get those stacks of Blight on their carry and keep hitting them until they realize they're being murdered. When they start to retreat, as soon as they start to retreat, start charging your Q. You know what to do.
7.) Build attack-speed and crits. Attack speed is vital for Varus, as it allows him to stack blight even faster. I'm going to be honest with you, I find the Champ Spotlight build to be complete garbage, and you'll have much better odds going for something like THIS. Whenever I see an allied Varus buy boots and pots at start, I shake my head, and about 10 minutes in my assumptions are usually proven correct.
8.) Varus can mid with hilarious results. I've mid-ed with Varus several times, against a few different popular mid-champs, and I can safely say that he is a very strong middle lane contender. Once you get to level 2 and have your Blighted Quiver, you should be winning lane rather quickly, if you don't have a gank-happy jungler on the enemy team.
9.) His Q goes through walls. That is all.
10.) 2 stacks of Blight is the minimum. If they have one stack, unless they're about to retreat, do not settle for the reduced damage. Try to get 2 or 3 stacks of Blight every time you fire your Q. Lategame once you have 85% crit and are landing about 400-500 damage per crit on them, this should be an instant kill on a carry that isn't stacking armor.
I hoped this helped you understand Varus a little bit. To me, he's definitely one of my favorite champs to play, if not my favorite.
However, to everyone saying Varus is OP, he really isn't. He's a carry with an exceptional laning phase, but he is very squishy and has no ability-granted escapes, especially if you pincer him. His E is simply a slow, and not even very effective at low levels. His R does snare, but if the enemy team is in a group and chasing him they will most likely be out of its range before it can spread to them as well.
In short, Varus is fine where he is, stop complaining, and please, stop embarrassing him by playing him badly.