Aside from what has been discussed, here's how I teach my begginer students. I call the first one In & Out. Cut all the way to the corner, then back out the blade. Turn the work 180°, with the teeth cutting into the waste side. Now, back the blade back into the corner. From there you can easily line up the blade to the line, then off you go. This works for very sharp corners.
The second one I call a Parallel Park. This one was mentioned above. Cut to the corner. Back the blade out about 1/2" or so, then widen the kerf about the width of the blade. This gives you enough room to turn the blade into the the next line.
With these two techniques you should be able to cut perfectly sharp inside cuts.
For sharp outside cuts, I call it a U Turn. Very simply, cut past the corner into the waste. Turn the work making a u turn then line up the next line, and off you go again.