Trophy level 11 (Observations on the Beautiful and the Sublime) was the biggest challenge for me so far. This level requires you to travel 4000 m, while lancing enemies along the way to refill a rapidly depleting life gauge. I put in several attempts over the last few days. When all is said and done, I must have invested at least 3 or 4 hours of time trying to get this trophy, but I finally did it!
Here are some tips for this level:
When you lance enemies, you refill your lance gauges as well as your life gauge. Early in the level, the game is generous with the amount of energy it gives out. Get into the habit of lancing at least 6 or 7 enemies on each attempt. I recommend you start a lance attempt by hitting a lance extender, and try to aim for lance extenders throughout--although you'll need to get a few regular enemies as well.
You can shoot your hook shot at enemies to propel yourself more quickly, as well as open them up so you can graze them for energy. Sometimes it's good to shoot an enemy just before you begin your lance, to get an added speed boost. As your lance fizzles out, you tend to lose speed, so you might want to shoot an enemy to keep your momentum up.
Once you get to the halfway point (2000 m), things get noticeably tougher. The enemy density appears to thin out, so you'll have to look carefully for a good lance opportunity. Also, lancing enemies won't award you as much energy as it did earlier. If you don't have enough energy to lance, then shoot a few enemies and graze them to regain energy, then lance again as soon as you can. There's very little room for error.
At 3000 m, difficulty appears to ramp up again. There is practically no room for error now. You must make every lance count. At this point, the amount of energy you gain from a lance attempt (even a rather successful one) probably won't be enough to replenish even one lance gauge. You're lancing purely to keep your life meter up now. Graze enemies, and then go for a lance before you lose too much life.
I strongly recommend that you line up your lance shots carefully, even at the late stages. It's better to take a second or two (but not much longer) to aim accurately and achieve a good lance, than to hastily jam on the square button and waste your lance on a failed attempt. After all, you gain nothing from a failed lance. Sometimes it's difficult to maintain composure, because you have the urge to keep the momentum going when the pace slows down, and will release a random lance as a result. However, if you can keep your cool, and maintain control, you'll be able to make it beyond the 4000 m mark and earn the trophy.