Just got Viktor because, well, i thought he looked badass honestly, but everywhere i go to see what you build and guides like that, are from years ago, latest one I found was 7.3. So, if you main Viktor or play him lots, help a newbie out. <3
played the old Viktor(original and after first rework) was a lot stronger, but really pretty sure mobafire.com and lolking.com have resent guides.
https://www.reddit.com/r/viktormains/
They can help you out.
Build order 
> >
/ 
>
If snowballing really hard 
if not 
>
Follow with 
>
get upgraded hexcore asap and use it on your E, Max E first, start Q, Try to harass enemy by aiming through minions you're csing at the same time for optimal effectiveness. get Q upgrade next and then W upgrade followed up with ult upgrade
Don't rush forward for kills unless you're sure you can get them in team fights because you leave yourself really vulnerable. Use W to cut enemies off rather than try and put it on them, poke with Q early on using the shield to win short trades. If seiging focus on waveclearing.
Always push mid if your midlaner leaves for 5 seconds or more, as hard as you can.
I reccomend 
