Well, probably a gravity assist. So, apart from the fact that I never used gravity assists in a controlled way and intentionally, I've got phase 1 figured out. Then I remembered him saying something about the escape direction being like a prograde/retrograde indicator. Well, I saw where venus is, and burned until the escape direction would be kinda retrograde to venus's orbit direction. And... I actually didn't mess up!
Dunno if this is good or bad. I think I still need to get a mercury encounter. Probably again a classic burn won't be enough, so I think I'll set it as target and burn at peri to maximize the oberth effect.