CSing is more important than just going for kills, as 15 CS is equivalent to a kill
CS list:
6 CS @ 2:05
How do you work on CS?
Go into a custom game
Buy your starting items
CTRL + Shift + o twice
Shift + S and tp to your lane
CS until 5:25 and you should be hitting 44.
Trading
Hit the enemy as he goes to CS. Do this by keeping track of your minion's health, once you see one that is about to die, you can start walking towards the minion to get in a auto/ability against the enemy. This works because while the enemy is auto attacking to get the minion, they can't do anything to prevent harass from you.
If there is CS to obtain for yourself, then prioritize that over trying to harass the enemy
Don't ever trade because "you feel like it". For example, you shouldn't ever walk towards the enemy, hoping something will happen. The enemy will either kite you or let the minions do damage to you, which will have a bad outcome for you. Never underestimate the damage that minions can do.
However there are a lot of moments that you can just go "all in". The above tips are mostly for ranged battles as top laners can generally go "all in" more often.
There are many things you should be thinking about, such as:
Level difference (a level difference is worth about 700 gold)
Items? (Does the enemy have armor/ item powerspike)
Cooldowns? (if your enemy wastes a skill for CS, etc)
Mana/HP
Summoner spells (you should always be pinging when the enemy spends one of his summoner spells)
Check the map for the jungler, your team should always be calling out the location of the enemy jungler. Make sure to have good vision before going all in.
Amount of minions? Tower aggro? (Negated by enough armor)
As you proceed to go all in,
Know your spell combo
How much damage can I deal?
What is my disengage if I fuck up?
How can I dodge skill shots?
Can I mindgame my opponent? (͡°͜ ʖ͡ °)
Obviously, this comes from having a ton of experience and knowing your matchup very well.
Warding
For top/mid lane:
Most junglers will clear out his jungle from bot side to top side and be at level 3 at ~3:10
Then the jungler will look for a gank
Therefore you should you should ward at 3:20
Control Wards
Make sure to buy these, these are valuble
Placing these in the river around the objectives (mid/top should ward the rift herald. Bot support should ward dragon)
Make sure you can defend the ward before you place it.
Lane Management
-When should you recall?
Recall when the minion wave is pushing towards you. This will minimize the minions you will loose when you recall
When is the minion wave pushing towards you?
If you shove the enemy wave into their tower, then the minion wave will begin to push to you because the location of the wave is far closer to the enemy than you.
So, if you kill the enemy laner, and know where the enemy jungle is at, ALWAYS try to push the wave into the enemy's turrent before recalling
If there are 4 more enemy minions than your allied minions, the wave will push towards you until it hits a champion or tower. The location of the wave does not matter.
Cannon minions can unexpectedly change up things. If a cannon minion is not quickly killed by the enemy minions, it will be able to change the way the wave pushes (less common).
If a wave is pushing towards your tower, you can freeze the wave right outside your tower.
It is okay to tank some minion damage as you tank the tower if you can freeze the lane right outside of your turrent
What is a freeze?
A freeze is when the enemy wave is larger than yours, so you can tank the minions outside of your tower range to keep the wave in a favorable spot
Here is a picture of the minions you need to push a wave from the blue side.
This can be useful knowledge to know when you want a wave of minions to slow push to your tower.