It's a unique experience working on excerpts over the years. You first encounter them as young as high school and, if you're serious, you'll end up playing them hundreds (thousands?) of times over the years.
As time goes by, you build habits...hopefully good ones. When bad habits creep in, sometimes it helps to play the excerpt in a different way.
One example is the famous/infamous Ride of the Valkyries. In a previous blog, I pointed out how your rhythm might be better if you related it to a familiar tune such as, say...The Mexican Hat Dance (see "Horns and Sombreros" in the archives.)
Here's a variation on the ride. Leave out the dotted rhythm and just play the downbeat notes.
Why? This variation should improve intonation and may help with developing a steady tempo. Put it another way, if you struggle with this version, the actual version probably isn't going to be a big success. Conversely, if you learn to nail this, it should help with final product.
Hope this helps.