How do you get different color of cloths?

If you mean "clothes"... You don't. There is no way to change Mario's clothes. At least, in the normal game. Some Gameshark codes can change his clothes, but if you don't glitch the game, you can't do that.

If you mean Mario's Hats/Caps...

To get the Red, Wing Cap - first you need to get 10 Stars, then a ray of light will appear at the entrance inside the Castle. Walk under the light and then look up at it to be transported to the Bonus Stage. Collect the 8 Red Coins for a Secret Star and then Ground Pound (A+Z) the Red ! To unlock the Wing Cap in every Level.

To get the Blue, Vanish Cap - once you've beaten Bowser the first time, head to the basement, unlock the door, follow the dark corridor to the right and enter the door. Go right, continue down the corridor and make the first right to a door without a Star - enter it, get in the water and swim under the wall to another room. Here, you'll find 2 pedestals to Ground Pound (A+Z) and drain the water - next, head through the door to be outside the Castle in the moat, make a right and follow the path to a hole. Jump down it, get through the area and find the Blue ! To unlock the Vanish Cap in every Level.

To get the Green, Metal Cap - you'll have to do Hazy Maze believe it or not. Down by that Sea Monster is a door in the wall at the far end - ride the Sea Monster over to the door, go through that door and jump into the Metallic Paining. Collect the 8 Red Coins for a Secret Star and then Ground Pound (A+Z) the Green ! To unlock the Metal Cap in every Level.

You can get color of clothes by using a CC(Color Code) To use it, Copy the code and go into options of PJ64. Next, Click Hide Advanced Settings. Then close it and go into cheats. Right click the White blank screen. You should see a option called "Add New Cheat" Click it and Paste your code in the second box. Name the color code in the first box. Then click add new cheat near the last box.Then click the cheat when it isn't tickmarked. Then close the Cheats Window and Ta-the! You just changed your clothes!

By saying 'cloths' (meaning 'clothes'), you need an emulator under ver.: 7.33. The only possible way found is with either 'Garry's Mod', 'Cheat Codes' or emulators. E.p:, 'project64', 'mupen64' or 'tendo64'. Sadly, you cannot edit the original game, only if you have the 'original' n64 game file. Hopefully this message helped you. I am not the best at modifications, but, the only possible ways to get coloured clothes in sm64, is by watching a legit tutorial, or following these steps.