If you will be working in close quarters attaching new molding to walls or ceilings with finishing nails, first check out your hammer handle. Inevitably the handle end will hit the adjacent surface in spots. Either use a new hammer, clean up the handle of an older hammer, or mask the end of the handle with masking tape, especially if the handle has an older covering of black rubberized material. Doing this before you start can save you time that otherwise would be spent cleaning up or repainting over the scuff marks.
Using thin wood wafers called biscuits can strengthen wood joints by providing more glue bonding area. You can use a biscuit joiner (also called a plate joiner) to cut precision mating slots in boards for the biscuits, which are available in three sizes. Or, to save money you can buy a kit to convert either your router or right-angle grinder. The conversion kits will generally cost about half that of a dedicated biscuit joiner.