talk to the guy that teaches you how to capture pokemon fly to cinebar island (not sure if thats the name in english but i think its the only island anyway.) and surf on the eastern coast up and down. you will encounter pokemon that arent normaly there that are level 120 sometimes. eventually you will encounter a glitchy pokemon. beat it, capture it (risky ive heard though nothing happened to me) or defeat it and the item in the 6th (maybe 5th? this is all my memory) will multiply ALOT. use this on masterball if your bored in capturing pokemon.
mew:
youd probably have to start over though play normally until cerulian (again not sure if thats the english name for the city. its the city with the water arena) city. then on the route after the bridge there is a boy that you MUST NOT fight. he is a teenager, looks to the south and has a slowpoke. keep playing normal until lavender town. on the route to the west from it there is another guy you MUST NOT fight. he looks to the north and is an actor if im not wrong. he is below the house you use to get to another route. play normally until you get fly. go back to the house you used to go to another route. SAVE!!!! because this one is difficult. go one step down and press start MANY MANY times. if you get in a fight you have to try again. if the menu shows up good for you. fly to cerulian city. if you press start and the menu doesnt come thats a good sign. fight the teenager and fly to lavender. go to the west and the menu will pop up. exit it and you will encounter a level 7 mew.
sunny town:
go to the saffari. save. shut the game. turn it on. try to get out. if the workers tell you that you cant leave or something like that go back try to leave again. if the same message appears save, turn off, turn on and try to get out again. (again this is all memory so youd better want to search this one to not waste your time). eventually they will tell you the same thing as if you just came. tell them you dont want to visit and get out. go to cinebar island and surf the east coast up and down. you will encounter safari pokemon that you cant encounter in different places (which is great since its a normal fight and they cant get away). eventually the gong of the safari will hit and you will be back there. leave the safari and you will be in a glitchy town called (in the internet) sunny town. good luck going there because you will probably get stuck sooner or later.
note: DO NOT save in the safari zone unless you can use fly. fly is the only way to get out of there. also, if you keep going north west (might be other directions too, i didnt try) the game will crash XD
ive heard you can encounter mew in sunny town but never saw him there.
those are pretty famous and i doubt you didnt know about them but hey... all kinds of people are on the internet. also, im not too sure about sunny town because again those 3 things are from my memory. so search them on the internet for clearer info
not tips i have beat white i meant glitches like the 1 before this post btw i know a few emerald glitches like cloning pokemon and items and how to get a pokemon with ??? hp
anyone want to know the emerald cloning,deoxys or hp glitch or the diamond/pearl cloning glitch(wifi required)or the black and white necrene city gym glitch(pointless but odd)or the skydrop glitch just ask!
