orbiting is a matter of horizontal speed more than vertical.
here everything has a fuel cost: raising you apoapsis (AP, highest orbital point) has a cost, raising your periapsis (PE, lower point) has a cost, and you start with a very limited fuel reserve. you don't want to just power your way to orbit (which is entirely possible!) because it's just easier to get to orbit softly.
that means not wasting too much energy in raising your AP!
try this craft: capsule, sas (normal sas), three fuel tanks, gimbaling engine.
now, we want to quickly skip trough the dense atmosphere, then start gaining horizontal speed when drag is less of a concern.
try this path: burn vertically until you are in the first light blue part of the atmosphere gauge, then turn 'right' at 45 deg and clear the second atmosphere 'zone'; when you're in the third atmosphere zone, get your craft horizontal and keep burning your fuel.
go to the map view: you'll see that even burning horizontally you're still raising your AP! keep on the map view, burning until the fuel is spent. you'll notice as your path will stop changing. see? your AP is now way out to space, while your PE is still too low so you'll do about an orbit and then crash into the atmosphere
so, if burning horizontally raises the AP, how in hell do we burn to just raise the PE without wasting fuel?
relaunch and do the same: burn vertically until you are in the first light blue part of the atmosphere gauge, then turn 'right' at 45 deg and clear the second atmosphere 'zone'; when you're in the third atmosphere zone, get your craft horizontal and keep burning your fuel.
switch to map view, and follow tha AP with the mouse. when the AP is at 100k, hit 'x', it will turn off your engine. notice that engine off doesn't mean stopping dead! you'll keep on the drawn path. keep on the map view until your craft is about to reach the AP, then return to the craft view (you don't need ultra precision here, even if you overshot it by a bit it won't hurt. but try not to!)
notice that your craft no longer point horizontal, so turn it until it does. (that's because the sas holds you to a direction which is absolute, while 'horizontal' is relative to the planet). when horizontal turn your engine at maximum thrust again and hit the map view
see? now the AP will change very slowly compared to the first launch (slowly because you can't be infinitely precise, otherwise it would not be changing at all) while your PE will raise dramatically. keep burning on even if you see that strange things will happen to AP and PE: that is when the PE raises above AP so they change points.
congratulation! now you are in orbit and you did your first actual orbital maneuver!
now this should make sense:
http://en.wikipedia.org/wiki/Hohmann_transfer_orbit 
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