End of the first movement, the descending pattern of E, D, C, B etc., this is the "fate of death" motif so really bring it out. You'll notice the descending pattern later on but it is much speeded up.
In the second movement there are very many long, slow notes. Don't glaze over and play them monotone. There is a different dynamic under almost every note. If you follow them, the piece sounds much better.
Third mov't - not hard, take a breather.
Fourth movement - There are a lot of notes. Fortunately, most are in patterns. It makes a great study for shifting actually. There are a few weirdly printed double sharps though, be sure to look at that so it doesn't slow you down the first time you look at it.
The hardest part about this movement is that it goes on forever, most of it forte or more. So, take it easy and let the tuba provide the volume and you provide the weight of the note. Save the mojo for after the long B dominant chord on the second last page, then let 'er rip.
Play lots to build up your stamina and do arm stretches before playing or you may do damage playing this piece.
Speaking of that long B, if someone in the section has a five string bass or an extension that goes to a low-B, they should play it with gusto on the B at the big pause.
The last bar will sound much more final if half the section takes it down an octave. Or better yet, the whole section plays a double stop with E on the A string and the low-E played together!
Guinness Stout is a really good beer to drink after this concert. Also, order a good potato dish and a shot of vodka.