Sounds like a fun project! There are many decoupage sites where you can get a lot of information. I suggest that you google!
That said: You should use elmers regular glue or something similar - school glue won't stick long term. And yes you can mix white glue with some water to thin it and use it as a coating. (This is basically what modpodge is, thinned white glue with a little bit of urethane) I prefer acryllic "urethane" to coat even for simple projects because its tougher and using glue can be sticky at times. Contruction paper may not be too thick, but it will fade over time. Stickers may bubble over time because of the difference in the glues and coverage. This may not matter for your project if it is subtle, however the stickers may not stick once you get them wet with the white glue or urethane. Some people who want to use stickers soak the glue off and glue them down with white glue. You might want to experiment with the stuff between the stickers or one from the same batch that you don't plan to use.
Good luck,
kathy

My parents wallpapered or just put borders in some rooms after last quake we had they surprised me by wallpapering the switchplates. You would use just the plain plastic ones, spread a little wall size all over,let dry. Wet the wallpaper & cut the corners just past the plate so you can fold under & get nice square corners ,when screwed back down nothing to fray or tear on edges. Just save enough wallpaper or border to redo if necessary. It's ususally pretty strong & lasts a long time. So she could have Tinkerbell on the plates too.just cut out part where switch is & be sure it's very dry before you screw back on or could get badly shocked!!! Mom's look great & it's been several yrs. Not decoupage but quicker & matches rest of room perfectly!! Also did the heating vents by ceiling cut each slat & it's held beautifully. Jan

I don't think decoupage is good idea for switchplate as it is used so much. I used to decoupage & layered same pic 3-4 times to make it 3D . If I understand you are just covering the switchplate. You may have wet hands, I don't think white glue based stuff will withstand that. I would have switchplates match border & then get creative & have your DD help you make a pic for the wall. She can sprinkle on the glitter with a little help from mommy (outside) she could put some stickers on. I made a corkboard for my DD & put it on her wall & we displayed her artwork there (pics for mommy & daddy of course went on fridge!!) That way she will take more pride in her room & get her creative juices working. Hope this helps! DD ate chili 1 night, I heard it come up,I picked her up & then put on the light-ugh Need to be able to wipe that area down. Hope I'm making sense to you!! Jan

I've done a few decoupage projects and for those which need extra protection I've used Diamond Varathane as a top coat. I use white glue diluted to the consistency of thick cream so it can be applied with a foam paintbrush to glue the paper to the object and a coat of that on top as well. When thoroughly dry I apply the Varathane.

I've never used construction paper and wonder if it's too porous. Of course you could experiment.

For beginner decoupagers I can't stress enough the importance of carefully removing all air bubbles. I usually use my finger and keep pushing them from the center to the outer edge and keep doing this until they are all gone. That's where the coat of diluted glue on top helps your finger to slide those bubbles out. If you don't remove all bubbles your project will look bumpy and it's not a good look! There are also various other ways of doing this. Depending on the type of paper used you can also dip the paper in water before gluing which "relaxes" it and makes it easier to glue. Not recommended for construction paper I don't think. Not sure what the scrapbooking paper would be like. I've used handmade paper and it was not easy to deal with. I never did get out all the bubbles and later used a pin and fiddled with it. Looked OK but it wasn't perfect to my eye.

I suggest you do a search as there's lots of info on the net on this subject and lots to learn. I'm not an expert but have fun with it anyhow.

Construction paper soaks up water & breaks apart so I don't think it would work. A tinkerbell fabric could be soaked in watered down white glue & would probably work & when really dry put on the varnish. Jan

HI Luckygal, I've never heard of diamond varathane. I'll have to look for it. I decoupage a lot of lamps. My last coat is bowling alley wax. It makes a hard finish. Don't remember where I heard about it. One lamp I did 18 coats of poly urethane then finally a coat of bowling alley wax.
kathy

concretenprimroses, the diamond varathane should be easy to find. It used to be by the Flecto co. but it seems they've been bought out by Rustoleum. It's a good top coat, doesn't yellow.

The bowling alley wax is a good tip, thanks. I've heard about that before but never seen it anywhere. I'll have to search for it. I'm amazed - 18 coats, I'm sure that's lovely!!! I've never done more than 6. Guess I'm a slacker! ;) JK I'm really just lazy and have lower standards. :)

Here is a link that might be useful: here's their link