Short of using protractor or mechjeb to get the phase angles you can eyeball the trajectory if you memorized them. The trick is once you think the planet is in the right place, set up your burn initially where you align your escape trajectory with kerbin's orbit and burn until you hit the target planet's orbit. Once you see the closest approach you can either wait until the intercept aligns, if you are early, which will save delta v. If you are late you will have to expend more delta v burning past the optimal path to shift your apoapsis or periapsis to an intercept. As for corrections the earlier you are the less delta V you need to make corrections, however, this also means it is difficult to make an optimal trajectory and fine tune the results. You can either use RCS or wait until later in the orbit where it is less sensitive to fine tune your approach. Also another trick if you don't want to memorize and eyeball the phase angels at all is to burn until you are slightly outside or inside the target plant's orbit(Whichever uses less delta V) and circularize it. From there you wait until your spacecraft is at the same angle relative to kerbol as the planet is. Once there just burn either prograde or retrograde(Depending on whether you are inside or outside the orbit respectively) until you get an intercept with the planet. This method is a surefire way to get you to another planet regardless of your planetary alignment however it does use more delta v and it also usually takes a LONG time. This is the method I used to get to eve before we had maneuver nodes, since I couldn't get an intercept even with protractor.
