For grassland, you could use ribbon or green string as grass. For the mountains, Styrofoam can serve as snow. Other methods recommended are things like paint and model magic or other air-dry clay that you could spike or create designs in if you want them to live in a house instead of their natural habitat.
For fire types (like Fennekin, Typhlosion, and Litten), keep them by a fireplace or a window where the sun shines through. For ice types (like Vanillite), keep them somewhere cool, like next to the sink filled with water, a bucket of water, or a pool. For water types (like Froakie, Oshawott, or Popplio), similar water places are also ideal. For steel types (like Beldum), keep them in a garage or near lots of steel. an electric socket For electric types, (like Pikachu, Pachirisu, Emolga, Electrike, or Dedenne, keep them near an electric socket or near a window so they can see the thunderstorm with lightning. For fighting types (like Hariyama), bug types (like Caterpie or Parasect), take them to the gym now and then. For grass types (like Snivy or Rowlet), they will enjoy being kept near plants For normal or fairy types, that will depend on what they do. Keep Munchlax in the kitchen, or Jigglypuff next to your karaoke system (because Jigglypuff is excellent at singing).
They might enjoy some Poffins with you. Poffins can be sugar cookies, dinner rolls, etc. Rare candy can be bought at stores in the shape of gumballs or chocolate balls, or you can pretend that you found new rare candy that is a gummy bear or some Smarties. PokePuffs (found as cake balls, cream puffs, or donut holes) and Pokeblocks (as Jolly Rancher candy) are great, too!
Phione loves Dora the Explorer. Joltik loves Zerby Derby. Paras loves Blue’s Clues. Swinub loves the Fairly Odd Parents. Treecko loves Go Diego Go. Squirtle and Chinchou love Franklin (you mean the turtle?). Weedle loves Little Bear. Venonat enjoys Little Einsteins. Aipom loves Ni-Hao, Kai-Lan. Pikachu loves to watch the Pokémon series. Pachirisu loves the Wonder Pets. Goomy loves Team Umizoomi. (Hey, that rhymed!)
If you bring them into a store, check that they don’t sell that plush there; otherwise someone might report you for stealing it from that store, and don’t ever put them down for a second. Try putting them in a backpack with their head poking out, or in a purse, but always check that they are still there in case they fall out. Only bring it to school on show and tell, and only have it out of your backpack when your teacher says so, you don’t want them taken away now do you?
When it’s washed, you can wrap the plush in a towel and give it a nice, long hug to remove excess water before sun drying. Machine washing may be okay sometimes but check the label first. If it has fuzz like Cyndaquil’s fire, then it is not a good idea to machine wash. Be sure to ask a parent before washing, as they might have a different suggestion.