I want to make a "good" schedule for a tournament between $N$ teams. Using memories from my (long gone) student days, I expressed it as a binary integer program. With the current set of constraints, and $N=10$, the resulting program has about $11,000$ variables and $20,000$ constraints. Is this considered large nowadays? The GLPK solver finds an optimal solution in about $20$ minutes, which is great.
But now I wonder if I could speed things up a bit. In particular, if I try to add some constraints, the solver sometimes takes much, much more time.
What tools or techniques can I use?
I can give a detailed description of the problem (or even show code), if that helps.