to do some home improvement activities, D.I.Y., to tinker away at, to fiddle with 
[verb]
[knut-se-len, knut-sel-de, ge-knut-seld]
There’s not really an exact equivalent in English for "knutselen". It varies from a handyman doing some home improvement, Do It Yourself chores, or children fiddling with paper, scissor and crayons…
Examples:
- "Nina heeft een mooie collage geknutseld op school."
("Nina has made a beautiful collage at school.")
- "Waar is Frank?" – "Hij is aan het knutselen in het tuinhuisje."
("Where is Frank?" – "He’s doing some home improvement in the garden house.")
- "Theo heeft het hele weekend besteed aan het knutselen aan zijn fiets."
("Theo has spent the entire weekend on fiddling with his bike.")
Related words:
- Knippen: to cut, to use a scissor [verb] [knipte, geknipt].
- Plakken: to paste, to stick [verb] [plakte, geplakt].
- Kleuren: to colour [verb] [kleurde, gekleurd].
- Prutser: screw up <person> [noun] [de prutser, de prutsers].
Example:
- "Frank is een totale prutser."
("Frank is a total screw up.")
- Prutsen: to blunder, to be messing things up [verb] [prutste, geprutst].
- Verprutsen: to mess up [verb] [verprutste, verprutst].
Ooooh I’m so excited to find this site. My husband is Dutch, and well, I know next to nothing. I’m going to surprise him with my improved vocabulary.
“knutselen” really is not about home improvements. It is what children do (and some adults): making an easter bunny out of a cereal box. Used in other ways it gets a diminutive meaning. If Frank is knutseling in the garden house, his improvements are more like a children’s job…