Please title your posts with detail of what your model actually is; low-effort titles will be removed.

When posting something new, use the link flair after you've made your post:

[Build] - Did you build it? Then this flair is for you! If possible, please include the download link

[Model] - For models that you've found online or elsewhere.

[Help] - For any questions you might have.

If you are looking for something specific in terms of tools, please mention your region.

What to use in general (refer to the sticky guide for more info):

Paper - use paper that is heavier than regular printer paper (regular printer paper is ~20lb/ ~75gsm).
Thicker paper = more sturdy model, but harder to cut/fold/score.
Thinner paper = less sturdy model, but easier to cut/fold/score.

Printing
Inkjet - ink and printers are cheaper to replace than toner and laserjets, and the edges hold up well after scoring/folding, but it doesn't print on all paper types, the resolution may be lower, and any moisture (e.g. sweat from hands) can ruin the colour.

Laser - able to print on all types of paper, can handle moisture, and can print at a higher resolution than ink, but can crack and flake off when scored/folded, and toner can be more expensive than ink.

Cutting - a self-healing cutting mat is an essential tool along with an Xacto knife or similar brand with #11 blades, or a box cutter knife. Scissors can also be used by themselves, or together with a knife. (ie. knife for detailed parts, scissors for straight cuts)

Folding - Run the back of your Xacto blade, or an empty ballpoint pen, or any similar small blunt edge along the line of a glue tab with enough pressure to leave an indent but not enough to cut it, then fold. You can do this on either front of back of a piece, but front is easier. Use a ruler (preferably metal) to help.
For curved parts, it is better to curl them around a round object (such as a coloured pencil or your Xacto knife handle) by rubbing the object against the back of the piece.

Gluing - recommending Tacky PVA/White glue (ie. Aleene's Original Tacky Glue in North America). Apply glue with a toothpick and evenly spread a thin layer of it on a tab. Use tweezers if tabs are small/too difficult to reach with fingers. Some have had good results with hot glue, especially on larger models - it is quick to set and won't cause the kinds of issues that "wet" glues have (paper rippling, ink smearing).

Useful Resources:

• Pepakura viewer (for the PDO file format)
  
• Beginner Tutorials
  
• Advanced Tutorials
  
• Card Modelling FAQ
  
• PaperCraft Wiki
  
• List of Compilations
  
• Technique Overview
  

Costume/Cosplay Resources:

• 405th
  
• the RPF
  

For any further questions, just ask the community at /r/papercraft. They will be happy to help.

Related subreddits:

• /r/origami
• /r/kirigami
• /r/papercraftcosplay
• /r/405th
• r/quilling
• r/paperairplanes