The key to getting into orbit is speed more than altitude. You need an orbital speed around 2300m/s to get into low orbit around Kerbin. You need to go up initially to get out of the thicker parts of the atmosphere, but then you need to work on your horizontal velocity. Going up, you are fighting gravity the whole time while horizontal you are only working against drag. This is why you need to use a gravity turn.
Each craft is different depending on its TWR and aerodynamics, but I like a starting thrust to weight ratio around 1.3 and try to keep my crafts as streamline as possible. By 4 kms