You can go ahead and use a slither.io hack in order to become invisible, to allow zooming in or zooming out, it allows for a god mode, getting faster and so many more.
The slither hack is also used for helping to get unlimited amount of mass. There are slither hacksites which are not restricted to a certain kind of device or single kind of operating systems.
Some tricks which can be used if one does not want to use a slither hack are :
When the snake is small, the snake should dash and eat and then move away. When it gets longer, then smaller snakes can either be encircled and so they have no other option than to run into your snake and kill itself. When the snake is longer it should be coiled and it should be left with the head slightly inward so as to prevent being killed by other snakes.
If there are large snakes that have been killed and leave behind a lot ofpellets, rather than rush to the site, you should wait as this is a place where a number of snakes get attracted in the hope of eating the pellets and in the melee there is real carnage created. If you wait till all these snakes have killed each other, you can go for the victor and thus prevent being killed accidentally.
Another method is to run ahead or speed ahead in front of slow snakes, as snakes get slower when they get larger in size. In order to do this the left click button can be used but in the process, you will end up losing some length. This however is a fair exchange. You get to rid yourself of larger snakes and can always increase in length later on.