I did essentially this transition. I trained in a DA-20, got checked out in the 172, and then bought part of a Cessna 177B. The biggest tip I can tell you is just to make sure that you are hitting your airspeed on final. (That should really have been driven home training in the DA20 anyway, so you should already have a big leg up.) Second, forget about the word "flare." Just think of leveling off just above the runway. When you think "flare", you then to pull up too high, and you balloon. If you just bring your nose up to level, then you can just fly down the runway, and let the speed bleed off. As that is happening, your goal should be to just try to keep the plane from landing, and gradually pulling back as you need to in order to prevent the plane from touching down. Eventually, you won't be able to any more, and the plane will just gently set down, nose high.
It really won't take you that long to make the transition.