Well the thing about the anime was that it was started right after the Saiyan Saga ended in the manga. So they already had a story and stuff to follow.
After that, though they were already caught up to where the manga was. So they had to wait for Toriyama to continue writing. Which is why we had some episodes full of nothing more then talking, or flashbacks, or filler with chi-chi, or Bulma or somecrap.
It was also the reason why the Garlic Jr saga was made, to give toriyama more time to write.
They recently released DragonBall Z: Kai, which was where they redid all the lines, changed the music, and got rid of ALL the filler, making it true to what the manga was like. For example in Kai the Cell games started at like episode 68, instead of the 100 something in the original dubbing. Heck the Frieza saga was over in 11 episodes I think, instead of the 30 it was before.