A medium-sized pair of scissors. Buying tools is not a good area for saving money and this is all the more true about buying scissors. They should really fit the modeller’s hand. They should not only be specially bought, but also not used for any other purposes. They’ll get blunt quite quickly if used for cutting cardboard.
A modelling knife with snap-off blades. There are two sizes of these available and I prefer the smaller one.
A ruler or setsquare, which also should only be used for modelling. It will soon convince us of that, covering itself with cuts and glue stains. Ideally, it should be made of metal.
A cutting mat, which is the modern alternative to what I prefer to use - a sheet of thick, plain, grey cardboard. The disadvantage of cardboard is that it has to be changed much more frequently than a plastic mat because of the cuts and the advantage is that it costs less and I risk very little if I spill glue on it.
Modelling or tailors’ pins. It doesn’t really matter what they’re called as long as they have large heads to hold them with and very sharp ends to drive them through cardboard.
Long tweezers. Not so very, very long, but long enough to help us in tight places where our fingers just won’t go.
Kebab or shashlik sticks or any other long wooden sticks. These are very helpful tools in card modeling, whether used for applying glue or helping out where even tweezers won’t go. They’re also a great help when rolling small diameter parts, acting as the cores of masts and yards on ship models and so on.
Glue. Were I to choose only one glue, it would certainly be a PVA-based glue, my second choice being a contact, rubber-type glue. The latter is quite smelly and requires some experience to use but still makes paper to cardboard gluing easier.