Here's the basic stuff I use:
1) Three- or more-view plans, 1/48th scale. I work from more than one set of drawings when they're available, as invariably some show things that others don't. Here I'm using Ian Stair's from the Datafile (naturally) and also the Alex Dumas three-view, which is very useful as it shows internal structure. They don't quite agree on major outlines, but that's alright. I've scanned them, scaled them, chopped them up and rearranged them so that all the profile views are together on one page and so forth. I've printed two copies, because I'm going to cut one of them into pieces almost immediately.
2) An X-acto knife and lots of blades, Elmer's glue, permanent spray adhesive and removable spray adhesive. I also use a little bit of CA for certain things.
3) Cardstock. I've chosen a light cream for the Pfalz and a somewhat darker shade for the MoS. MS356 has the serial number painted in gigantic fancy numbers on the sides of the fuse, and you can see that I've printed this detail (and a faint outline of the fuselage profile) onto one of the pieces of the darker card. I drew these and the other markings I'll need in Photoshop while I was laying out the drawings. I printed two sets, just in case. I'll also use some brown and black cardstock, as well as colored paper, white paper colored with markers, and different colors of tissue paper.
For me, one of the advantages of scratchbuilding is that the weight of the stock isn't crucial; a commercial kit has been designed to use a specific thickness of stock and if you don't use the same weight the designer did, you can have some very annoying fit problems.
4) Markings printed on tissue paper. This page includes the French roundels and rudder stripes,
eisernekreuze and red/white wing and fuselage stripes for the Pfalz. The tissue is adhered to a carrier sheet of regular paper with removable spray adhesive and goes through the printer with no problem. I sealed this with a few light coats of a clear acrylic after the ink dried, and peeled it off the carrier sheet. You can see how translucent the tissue is; I'll hit the back with a coat or two of white spray paint to opaque it up. I use tissue paper because it's thin enough to not look like a "layer' when it's glued to the model. Again, i make a point of prining as many extras as I have room for.
5) Cutting mat.
6) Circle template, for drawing and also creating circular things like control wheels and gun rings from long strips of paper.
7) Olfa circle cutter. This is an outstanding and indispensable tool. It'll do a circle from just under 1/2" diameter up to around 8". Buy one. Perfect for paper and card, it will also do thin balsa and thin plastic.
8) Metal ruler.
Metal.
9) Small drill bits. This particular set is made by Dremel, but I rarely use them in my Dremel tool. They're handy for making holes in cardstock (just twist them by hand) and also as mandrels or rolling parts around.
10) Hole punch, with different size punches. The family hates it when my normally quiet hobby requires me to start whacking this thing with a hammer.
11) Straight pins, for poking holes and making propellors and engines spin.
12) Graph paper, 10 squares to the inch. I tape my stock to this for drawing parts.
Tomorrow, I'll start to build.