These are all pretty simple, so I won't go into great detail.
Problem: Corn ethanol is highly inefficient.
Stop subsidizing it. Instead, subsidize research into switchgrass/cellulose ethanol, which can be much more economically and carbon efficient.
Problem: Subsidies of sports stadiums don't provide economic return of the magnitude of the subsidies to cities and are highly inefficient.
Solution: Make them illegal or subject to some sort of national (i.e. not that-local-sports-team-oriented and not-dependent-on-that-locale-for-elections) oversight board
Problem: We don't have enough good public schoolteachers.
Solution: An ROTC-style program where people take education classes outside of college, and then enroll as a public schoolteacher for 3-5 years (you can make it "in neighbourhoods whose need is large, defined by some permutation of graduation rates") in exchange for a tuition grant equivalent to the amount of tuition at a typical in-state public school (or more, if that's efficient).
The exact numbers of years and magnitude of tuition-waivers at which this is efficient can be figured out pretty easily with data, but the structure can make sense.