This picture shows the most important tools at all.
– A super fine pencil to mark the parts before drilling or cutting. I probably used 10 of them up to now.
– Rulers with fine ruling. Made from metal, so you can bend it. You need to buy this from US or GB due to the inch ruling.
BTW: Inch ruling is a nightmare. Being used to metrical Millimeters, it costs a lot of nerves to get used to this 13/8, 7/16, 3/16, 1/4 inches. Do you know what this means in millimeters? This inch based ruling is a permanent root cause of errors. Why does anybody still use this anachronistic system?