For a Dapol Kit (which I do like to build) you will need a sharp craft knife too and a little set of needle files. They are cheap. The kits these days have a lot of flashing because the moulds used are a serious age. Also, gather a few photos of the finished models to help positioning of finer details.
By the way, some of the original Airfix kits occasionally appear unbuilt. There are a few on Hattons Preowned right now for £3 to £5. The plastic is better, the box is cool, but if they are wagons they will come without tension lock couplers.