The perfect body position for swimming any stroke is to be as horizontal and high as possible on the surface of the water – essentially aiming to swim over the water rather than through it.
This is why people find it easier to swim when they have a pull buoy between their legs (lifts the legs up behind you to level you off) or wearing a wetsuit (lifts the whole body up in the water, reducing the resistance).
Working on your body position should be the first thing that you improve as a bad position increases the stress on the rest of your body, so regardless of how good your pull and/or kick become, you’re always going to be working harder than you need to.
Opinion on where to focus your eye line varies, but my suggestion is to think about standing as tall through your spine in the water as possible. This will invariably encourage your view downward, at least slightly, but different people will find different optimum points.
The added benefit of this lengthened spine is that you should be encouraged to engage your core muscles. The combined effect of this should turn your body into a seesaw, lifting your hips and legs toward the surface of the water. Every effort you now put in will be concentrated on pushing you forward.