The trick I use, is have a duality to every action of the character (I write short stories). Every single thing they do should 1), push the story forward, and 2), give information about the character, or the setting.
Here is something I would write when writing novel perhaps:
Paul parked the car, opened the door and stepped out. He closed the
door behind him and looked at the abandoned farm house. The wind was blowing trees enough for them to bend, though he was sure it wasn't going to rain. and he remembered a time when he was still a boy
here, and played in the fields. He remembered playing with Emily, who
at the time was her neighbor, although he hadn't thought about her.
She was a good friend, though he didn't care much that he hadn't kept in contact with
her. She still lives somewhere in the region, but that wasn't important to him. Without further
ado, he took one last drag from his cigarette, extinguished it, and went up to the house, let his hand pass over the wall. It's
surface was rough and worn through reminding him of...
Here is the same idea, but with more detail, in fewer words:
Paul parked on the grass, stepped out, ashes from his cigarette
carried by the wind. His childhood farmhouse, worn-through with age,
reminded him of childhood friends, though they were long gone. He extinguished his Malboro Light on the ground beneath him and
followed the path to the house.
- Emily isn't important (in my story); the fact that Emily existed, does, hence no description of her
- Parking on the grass gives a hint on his disrespect for nature. Extinguishing the cigarettes on the ground does as well.
- Exact brand of cigarette hints at who he is as a person.
- The fact he follows the path to the house suggests that he has respect for the social customs however.
It is basically a removing of information that doesn't serve less than two purposes, or exchanging generic words to more specific ones in order to convey more than one message. Writing like this, for every single sentence, all the way to the end, will allow plenty of time for a reader to care for the character.