If you need help: I have documented the design and build of many of my models...
and you can find this information and more at www.papermodelforum.com. 
There are also some photo reference collections there, that you can view. 
Register and open a free account there.
The forum is a great place to ask questions, get advice, and share your progress.
Well, first you need to print your model pages (if yours is a digital model).
Pay attention to any printing instructions that are provided in the kit and on individual pages. 
Cardstocks are used most often, however smaller parts can be printed on lighter weight papers.
Some builders like to use glossy photo papers for some elements of their builds although I shy away from them. 
I generally use 65lb/176gsm cardstock for just about everything, but that's just me. 
You can print your models at home, using your pc printer.
Or you can take the pdf files to your local print shop. 
Take advantage of the highest quality print settings to get the most from your models!
As you gain experience, you will definitely expand your collection of tools to suit different types of models and building techniques that you will encounter.  But to start off, you will require some of these basic tools: 
A CUTTING MAT...to protect your work surface and save on knife blades!  These are available in various sizes and types at craft and art supply stores. It pays to invest in a better quality mat, which will also last longer.
SCISSORS...to separate and cut out parts. Large and small,  
You might consider an assortment of scissors to suit different cutting needs. 
A HOBBY or CRAFT KNIFE...for more controlled and precise cuts. 
Extra blades are also necessary to make sure you are always making the best cuts. 
GLUE...a paper glue to suit the paper/card you are using. The variety of glues at craft and art stores will suit everyone's tastes. Most modelers have an assortment of glues for different applications. I especially like "tacky glue".
TWEEZERS for holding and handling small parts. I have a large assortment.
STRAIGHT EDGES and RULES...mainly for cutting straight lines, but also for measuring. 
Make sure to use metal or similar for your cutting edges! Plastic Rules are a mistake.
PAINTS, PENS and COLOURING PENCILS are all used to colour the cut edges of paper parts, as well as making small touchups and repairs to printed parts. 
* SPRAY GLUES for gluing larger sheets and laminates. 
* SPRAY FIXATIVES and CLEAR COATS for protecting printed pages and sealing inks.
By using this site you automatically agree to all related copyright and intellectual propety laws. All designs and images are the creation of, and the property of: Dave Winfield © Dave's Card Creations, davesdesigns.ca.  Any and all paper model kits found here are designed for personal and private use only and are not to be sold. The basic templates, designs and PDF files are also restricted from public sharing without the express permission of the author. Tags: paper model papermodel card cardmodel dave winfield airdave cutandfold paper model shop usaf raf canada forces hercules mustang thunderbolt saladin centurion tank military vehicle pt boat u-boat aircraft apollo rocket hobby tutor snowbirds spooky gunship p47 p51 b24 c130 
Like with any skill or talent, practice and making mistakes are the best way to learn and get better at whatever you are trying to do. Don't be discouraged by other modellers who have learned their craft over many years.
Experience takes time.. 
With a little practice you can master some of the basic techniques of paper modeling. 
Try building a basic "scale cube" model (available for free). 
Also try rolling tubes of various lengths and diameters and gluing them.
Try to print all your model pages at the same time, on the same card/paper and using the same printer (and same settings) ...this ensures all your parts will match in colour and quality. (Note these things for future printing)
Always check your printer's settings:  
Print every page at 100% full size, no scaling.  
Make sure not to allow "fit to page" or "shrink to fit" as this will change the scale of each page individually. 
And, print on the highest level quality for the best results.
Examine your printed pages carefully before cutting out parts and pay attention to any special instructions printed on the pages. Also get familiar with the part numbers and locations. 
Prescoring your fold lines before you cut out parts is a lot easier. Use a fine, blunt tool and a straight edge (wherever possible) to create easy to fold lines. Always be careful not to score too deeply and cut into the paper fibres. 
If you cut out many parts at once, why not number them on their reverse sides for easy reference...but make sure to use light pressure with a soft pencil. 
Always dry (test) fit all parts before gluing them together to make sure the parts fit correctly and to make sure you fully understand the assembly. This is where you can trim parts if needed. 
Make sure you can see what you are doing!  Good lighting and magnifying lenses come in handy!