Quick guide to getting into orbit:
Take a command module, add 3 fuel tanks, a LFR and nothing else. Not even SAS.
Takeoff at full thrust and keep your rocket pointed perfectly vertical. This will need alot of small adjustments without a SAS so keep your eye on the ball thingy. I forget what it's called.
At 25,000m pitch your nose all the way down to 0 degrees at the horizon line on the ball and hold it steady. This can be in any direction, I prefer to go east because i'm used to it in orbiter where going with the direction of the earths rotation help you achieve orbit. I don't think Kerbal rotates, but it would be a good feature.
Anyways When you reach 40,000m cut your engines. Now, keep your eye on the green/yellowish direction indicator circle on the ball. When that reaches 5 degrees, or just above the horizon line go full thrust and keep directed at the center of that circle untill you're around 2,300m/s and then cut engines. Congratulations, you just got into orbit with the smallest possible rocket. You should have enough fuel left over to de-orbit but you'll crash and die. de-orbit worthy spacecrafts need a bit more power.
Theres better ways to get into orbit then pitching your nose right from 90 to 0 but it's simple. With this I got an apoapsis of 64,000m and a periapsis of 42,000m but yours will probably vary.
If you drop your nose to 0 at 20,000m and have good control of your thrust and pitch you can achieve a near circular orbit at the very edge of space. (space beginning somewhere around 34,500m)
I've been doing some experimenting with thrust levels trying to optimize fuel consumption. These used a command module, 1 or 2 SAS modules and a LFR with 1 fuel tank.
1 SAS at 50% thrust: 28,166m in 2:46, top speed 415.2m/s
(This was the minimum thrust needed to get liftoff. For the 50% test I moved it down just after liftoff)
1 SAS at 62% thrust: 28,267m in 2:34, top speed 438.9m/s
1 SAS at 62% thrust, moved to 52% at half fuel: 28,607m in 2:37, top speed 426.3m/s
1 SAS at 75% thrust: 27,293m in 2:20, top speed: 455.9m/s
1 SAS at 100% thrust: 20,834m in 1:40, top speed: 456m/s
2 SAS at 62% thrust: 19,029m in 2:18, top speed 306.6m/s
2 SAS at 75% thrust: 19,116m in 2:08, top speed 327.8m/s
(This was also the minimum thrust needed to get liftoff, same deal as the other)
2 SAS at 75% thrust, moved to 65% at half fuel: 19,295m in 2:11, top speed 316m/s
2 SAS at 100% thrust: 16,275m in 1:32, top speed 364.3m/s