Understanding the Laning Phase
Why do you need to learn about laning? Because it is the first stage of the game, if we want to win we have to start off well! Laning specifically refers to the period before the first map objective comes up. During the laning phase all there is to do on the map is to try and push down a lane, killing the minions and towers, but laning is important later in the game too.
First: Assess the situation
What heroes am I up against?
This is important because some heroes are just flat out better at winning the lane phase, these heroes are often specialists and assassins that can clear the lane minions quickly.
How many heroes am I up against?
Two heroes are always more likely to win than one!
Second: Make a battle plan
There are many ways to win this phase:
You can outpush your enemy so that your minions are reaching their towers
You can kill enemy heroes
You can soak experience while your teammates push other lanes in your favor
So what strategy should you go with? Its going to depend on what hero you are playing. Heroes such as nova have an extremely hard time out-pushing their enemies, simply because they have no Area of Effect (AOE) abilities. For these heroes its better to take one of the other two strategies, for example Nova is great for killing enemy heroes.
You also don't need to stick to just one of these strategies, for example if you're playing Tassadar your strategy might be: Shield myself and auto attack the enemy hero, use my Psionic Storm (W) on the lane minions. This will force the enemy to have to choose between stopping me from attacking their hero, and my lane minions attacking their base.
Third: Carefully watch mini-map and execute:
Watching the mini-map as you execute your plan is very important. Often people move between lanes, to surprise and kill enemy heroes. By watching the mini-map you'll know where enemies are and anticipate their movements.
For example: I see all 5 enemy heroes on the mini-map so I know its safe to push my lane
Or: I see only 1 enemy hero on the mini-map, I should back off before I get killed
Winning the laning phase is important because it sets you up for the rest of the game. A small level lead early on often cascades into a bigger level lead later on.