I'll put it out there off the bat - I am hopeless at actually doing anything myself. I'm great at coming up with ideas but have someone else to do the work for me. But, if you are good with your hands and have the time, here are a few things that could potentially be on your list ...
1. Nothing shows its age quicker than a dated vanity. To make your life easier, try to replace your existing one with another of similar size to avoid needing to patch walls or tiles to fill in the gaps.
2. Re-groute and silicon tiles. If your wall tiles are in good condition, a good clean and new groute could make your bathrooms look like new! Another option is to try your hand at retiling the walls if needed. Careful when taking tiles off though as you would not want to damage your waterproofing.
3. Change up your tap ware. Old taps, shower heads and accessories can let the room down.
4. Artwork is always a great idea in a bathroom.
5. Plants are suitable in all rooms but mostly in a bathroom! Make sure you choose plants that need and thrive in a lot of moisture.