How do I make my house smell lovely?

I personally wouldn't want my home to be filled with artificial fragrances, most of which contain a toxic mix of chemicals. Candles, plug ins, air fresheners, diffusers, all are bad for health, especially for young children, asthmatics or those with lung conditions. Look it up!
Just open windows. Artificial chemicals just mask normal smells.

Change the scent often , you get used to one scent and can’t smell it after a while

Of course you do air the place and make sure cooking odours etc are dispelled ?

I like this www.amazon.co.uk/Aromatique-SMELL-SPRING-Aerosol-Spray/dp/B00PD1AZOW?tag=gransnetforum-21

I'm just about to try a scented oil diffuser which uses essential oils in water and puffs them into the air. The one I've bought is wood grain and looks attractive. Search 'scented oil diffusers' on Amazon.

Fresh flowers, (hyacinths at the moment), fresh air, washing dried on the line, Aldi No. 1 Jo Malone lookalike (smells like) scented reeds - Lime, Basil and Mandarine.

Use scented furniture polish - also scented candles.