First example You are using a level 100 Tauros which knows the following moves
Remember to assess your opponet's weaknesses both it's type and it's stats. Also remember your own pokemon strengths. It's most powerful attacks are most likely those that match it's type. Unless you are using a pokemon that is low in the stat that it's type moves are based on. Examples would be Kingler- a low special water pokemon and Onix-a low attack rock,ground pokemon.
Train your pokemon well and your advantages will be more pronounced and your disadvantages will be less. If your pokemon's stats are high enough you can even overcome a type disadvantage. My Dragonite is well enough trained that is can easily survive a blizzard attack from any average special, non-ice type pokemon. This is something that you can't say for a rare candied pokemon. My nephew and I battled are dragonite's against one another. I let him attack first by switching pokemon. My Dragonite took a a blizzard attack from his rare candied Dragonite and didn't faint. My dragonite then proceeded to faint his with one hit from a much weaker ice beam attack. So you can also take into consideration how well trained your pokemon are in comparison to your opponet's pokemon. In pokemon stadium's round 2 they are EXTREMELY well trained probably most are near or at their maximum. Ok time for another example.
You are using a Vaporeon your moves are as follows:
Your opponent is using a Tentacruel OK now what move should you use? Got an Idea? OK hold that thought. This battle actually happened in Pokemon stadium. I think it was round 1 prime cup masterball level. Tentacruel is obivously much faster than a vaporeon it also should have higher special. Tentacruel and Vaporeon are numbers 1 and 2 in terms of highest special water pokemon. Of course every move listed would come out as not very effective on the Tetacruel. Vaporeon and Tentacruel were the last two pokemon so I had no choice but to battle it. The computer opted for a wrap strategy. This was very annoying if not particularly effective. Vaporeon's high number of hit points and tentacruel's low attack combined to make the attack only do miniscule ammounts of damage. So what attack do you think I chose to use? I used hydro pump mostly because of it's extreme power so as to overcome the type disadvantage and to matck vaporeon's water type. Every time that the tentacruel's wrap would miss, my vaproeon would use hydro pump. It took a good while and it was a little close but I finally won. So remember this battle and remember that good stats and persistance can win battles.
OK now why don't you try a little quiz to see how good you really are. If you haven't already go to the 150 By type or over to the Universal Pokemon network(look under the pokedex) to see the stat ratings of all of the pokemon then come back and try the quiz!