Early game start off is critical for a successful game. How to have a great laning phase, and have a positive impact on your team?
Laning phase last around 1:45 minutes to 15:00 minutes or when you destroy their first tower, this is considered the early game in this phase of the game you will most likely be by yourself unless you're bot side in that case it will be a 2v2. Having a good early game is key to having a successful game, and helping those who need it most will make it so you have a positive impact on your team. In laning phase gold and experience are the two things you will want to have more of then your opponent.
For top laners, mid laners and "adc" the way you get gold is by "cs" killing the minions or killing your opponent, easiest/safest way is to get more gold than your opponent is to have more "cs" then your opponent. Killing a champion only gives you normally 300 gold, that is worth around 18 minion kills or less depending on the minions you killed. As you can see it is a lot easier to go for "cs" over trying to kill the enemy champion, not saying you should not try killing them but keep in mind that by trying to kill them you might be losing out on "cs"/gold.
Being able to out trade your opponent in the early game will make it harder for them to "cs" giving you the edge you my need later on in the game. Some champions have better early game then others using that to your advantage is important to find out if your champion can out trade an opponent, also some champions counter other champions making it easier to win laning phase. Knowing when to "poke" the enemy champion is a skill that comes with practice but i can tell you that when the enemy spells are on cooldown "cd" that is the best time to hit them if the conditions are right.
What i mean by "trade" is when you and your opponent "poke" each-other, winning a "trade" is when you did more damage to them then they did to you. At the same time you don't want to be so focus on "trading" that you miss out on "cs" to hit the your opponent. Some players are so aggressive that they end up missing most of there "cs" just to "poke" their opponent hoping that it will pay off in getting them a kill. There is a time to "trade"/"poke" and there is a time to "cs", knowing when you should focus on one or the other is key to winning laning phase.
Having a positive impact on your team will help you and your teammates, by helping those who need it most by "roaming"/"ganking other lanes". what i mean by "roaming" is when you go to other lanes to help out your teammates kill their opponents, "ganking" is when you try to catch your opponents off grade by going to the lane without them noticing you and hopefully make a kill out of it or at least try to. Doing this can be helpful to you and your teammates but it can cost you gold/experience that you could of had if you stayed in lane, only "roam" if you see an opportunity or want to help out a teammate that is having a hard time in lane.
Note: Junglers are always "roaming"/"ganking" other lanes to try and help out the team so be careful for the enemy jungler, as a jungler it is important to try to help out the lane that needs it the most to keep the enemy from getting overwhelming "fed".