Re: new and need alot of help
There are a lot of factors that determine the ratio of pokemon appearances. Most of this is easily solved by location, and then by the rarity of the pokemon itself. For example, the chance of finding sa Tentacool in any body of water is incredibly high, since they are common pokemon. However, the chance of finding a Bagon, a pokemon worth the long wait for Salamence, can only be found on the lowest level of Meteor falls, and Zubat's are still the predominant pokemon, as in any cave.
Hope that helps. For exact ratios, go to the Bulbagardens page on any specific pokemon you're looking for. Good luck with your game!