Number 1 rule: Stay waaaaaay ahead of this airplane.
Number 2 rule: Don't rely on VNAV to manage your altitude AND your speed. In the terminal environment I almost always intervene with a reduced speed and then just dance on the speedbrakes to keep a descent rate of descent.
*The other thing to remember is that the 777 will often put itself above path while descending (keeping it comfortable for passengers while the pilot wonders what the heck is taking so long). If you're busy trying to get back on path while continuing to slow down, you're going to have issues. Just get used to it and start managing your speed earlier in the approach.