What are some home-made decorations I can make for a Sponge Bob party Theme?

Get some posterboard and either paints or markers and scissors .
Draw out a spongebob , pinapple , plankton , patrick , krabby patty and cut them out and hang them around the house .

blow up a bunch of yellow balloons . But some streamers . Yellow ones .

tablecloth try to find a blue or yellow one or tropical one at the thrift store

you can bake a cake and decorate it so it looks like sponge bob
as party favors u can prints coloring pages of the internet and also they have some activities u can do

heres a link with different sponge bob activities/ideas:
http://www.dltk-kids.com/Crafts/cartoons/spongebob.htm

get some small boxes, and wrap the top half in yellow paper, the middle in white paper, the bottom half in brown paper. Add his tie and face.

You could make your own sponge bob pinata, same basic way as above.

Get paper in different colors, and cut out the flowers that are always in the back ground, tape them up on the walls.

get a bag of sea shells fron the dollar store and spread them out over where

Get a couple of fresh pineapples and set around.

Freeze a red koolaid in ice trays and use these as ice cubes in oj. You could also freeze strawberries and ice cubes. Make sugar cookies in the shape of starfish and sea creatures, Use coconuts to drink out of, Have pineapple and fother ruit shiskabobs with vanilla yogurt dip.

Make SpongeBobs!
This is one of the coolest kid party ideas for a SpongeBob icebreaker activity… Get a bunch of regular-sized yellow sponges, yellow and white pipe cleaner (for the legs and arms). Have some markers, craft paint, glue, white paper, brown paper, red paper for the tie, and have the kids create their own SpongBobs. Make sure they have a few pictures of SpongeBob around to inspire their creativity.

SpongeBob Kid Party Ideas for Food
Here are some kid party ideas for your SpongeBob birthday party cuisine. Remember to put small signs on each dish just to make sure everyone understands that they are munching on real SpongeBob food:

Mr. Krabs Patties (hamburgers)
Mrs. Puff fish sticks
Seaweed pasta (Green linguine)
Squidward-dogs (Hotdogs that look like tiny octopuses. Cut all the hotdogs in half – but not all the way – only so that they open. Then slice halfway up four times on each half so that you have eight dangling sections and place in boiling water. Watch them curl up like arms!!!)
Gary’s Submarines (Subs!! you can make this a buffet where everyone makes their own subs)
Plankton pizza (mini bagel bite pizzas)

SpongeBob Kid Party Ideas for Drinks:
SpongeBob Ocean Slushy – Mix 3 cups of ice, 3 cups of blue sports drink or punch, and 3 large scoops vanilla ice cream or frozen yogurt in a blender. Whirl until smooth and serve (place the shake in the freezer for a thicker shake).
Blue Punch (Put gummy fishes or gummy sharks inside. You can also freeze the gummy fish and sharks in cubes of ice)
Pop Rock Punch (This is another variation of the Blue Punch. After you’ve placed a filled glass in front of each guest, add some seaweed dust (a few Pop Rocks candies) to each cup. It will then crackle, pop, and split when it comes into contact with the liquid.)
Jelly-fish liquid (pink lemonade)