To counter jungle correctly its all about knowing timing about jungle camps and anticipating your opponents movement. You want to either force a vertical jungle situation where you and your opponent trade sides of the map so you take the whole one of your buffs and one of your enemies and he take the other side, or you take a couple of camps from your enemy making sure to clear the entire camp if you are stronger then him and kill him when he tries to kill it, or leave one monster so that they lose experience having to clear one monster and waiting for the camp to respawn. One thing you have to know is that if you took there camp once they will most likely ward that side jungle after recalling so you don't have to worry about wards until the camp is about to respawn. You can look up some common ward spots so you can know where to clear the ward, or use the first ward tip in order to help you avoid those wards without clearing them.
If you are looking for straight up tricks there are 2 very important ones you must know
First 
and 
disable regular wards so they will not show the area around it, BUT they will show you if you auto it, so if you want to take a camp without them knowing you are there it would be in your best interest to use and and not destroy the ward but take the camp first.
The second trick goes along the first one but when you destroy a ward for a half a second or so after they are destroyed they will still reveal you and potentially show where you are going, so what you want to do is after you destroy a ward move in a direction you don't want to go for a split second then turn around to go where you want to go this will trick more high level opponents that know about this trick.
Lastly tip is extremely situational and as a shaco main I use it whenever the chance presents itself, but if you are going to back soon and a opponent drops a ward you could place a shaco box on top of the ward so you know where the ward is without having to actively think about it later on and using that knowledge you can think of a different way of approaching that lane.
These are some tips that I have but I am only in silver/gold so take everything I said with a grain of salt.
ucked everytime I go in there.
Is there any tutorial I could use about jungle vision? Everything I found is about doing the scuttlers and ganking, and it's not really what I need.
to check bushes or camps before going into them? I typically don't counter jungle whatsoever but I also don't play ranked. Other than buying 