Cannot say for your particular countries regulation requirements.
Off the mark, use a proper IEC input socket for your power input, you can get ones with a built in fuse holder. (no need for test and tag, no need for strain relief)
next to the jack should be a mains power switch, if you want to play safe use a double pole to break active and neutral, this way if an outlet is wired funny you are safer with it switched off.
If your system is noisy, or is highly susceptible to mains noise, you may need a mains filter, X and Y filter capacitors with an optional common mode choke. If your running it directly to a transformer, then you likely don't need a mains filter, as the transformer attenuates any frequencies higher than mains.
Ground your casing if its metal, use a wedge lock washer if you want to make sure it never comes off.
Do not rely on only solder for mains connections, you must mechanically support them, IEC sockets will generally accept crimp terminals, IF your running mains directly to your PCB, use a connector, not direct wire to board, leave 2x 3mm holes nearby to the connector to zip tie the loom to the board so the plug never tugs loose.
To give an idea of why the respect of using say insulated crimp terminals instead of soldering. if the 2 mains conductors touch, there can be a fault current measured in hundreds of amps for a general home wiring circuit. solder joints if the wrong flux is used or the joint experiences vibration becomes brittle over the years, meaning a wire can break off and touch places it shouldnt, the crimp, not so much.