Don't catch heaps of weak pokemon and never use them.
Just do what I did and get a starter (I got WINdiquil) and catch a pidgey right at the start.
Should get you through the game until after goldenrod city.
Catch the sudowoodo at that point because it is beast and at good level.
Maybe catch a paras in ilex forest for cut and rock smash.
At olivine city catch another pokemon for surfing and fighting.
According to this formula you should have:
Fire (cyndaquil) or grass or water
Flying
Rock
Water (or grass if you have totodile)
probably an electric
and a filler.