If you arent good in lane phase
Assume every engage will end in your death, and assume the jungle is always in river looking to gank you.
If you live by that credo, you will focus on safe CS, and NOT feed your lane, Then someone else can carry, and you can bring damage, and if top or tank, a meat body to teamfights, without a fed lane as baggage.
And over the course of alot of games, by not dying all the time, you will have slowly learned to be safe and avoid getting stomped like a "noob", and will likely be more comfortable being offensive and fighting, because you will have spent a bunch of games warding responsibly and dodging poke/skillshots, which might help you start to actually fight people. Not to mention learning better CS is something nearly everyone can work on.