Why are there always so many replies on these threads saying you like your washing to smell of nothing
that's nice for you but OP has a different question.
I had the same question OP and this is what I've found helps.
Dry quickly - Tumble dryer, or dry outside - and never leave laundry in the machine after it finishes. Try and remove it ASAP.
Detergent-related -
Highly scented washing powder e.g. Lenor, or Bold 2-in-1 is lovely.
Use about a cupful white vinegar instead of fabric softener
Match fabric softener and unstoppables to the powder (but it is possible to get a nice clean-laundry smell without unstoppables - I don't think they are necessary, and they are very expensive)
I did try pods for a while thinking they might be better - mixed results with these.
Check what the dosing instructions say as well especially if you live in a hard water area. I was using much less than recommended, once I used the amount recommended for the water hardness and load size, I got better results.
Water-to-clothes ratio -
Modern washing machines only use a small amount of water, and the dosing of the water is done on a timed basis rather than measured. It's worth checking your WM manual to see what it suggests for the installation of the water and if you want to be really pedantic, check the flow rate from the input tap. For example, mine says it needs a flow of 10L/min and you can check this by turning the inlet tap off, unscrewing the water hose, placing an empty bucket under the tap and seeing how long it takes to fill up to a 5L level. If it takes more than 30 seconds the water flow might be too low for the machine and you might want to consider changing where it's installed.
But also - I've noticed that if I have my cold tap running and my washing machine starts to pull water in, it reduces the flow from the cold tap, so I assume the same thing is happening in reverse. When your washing machine is filling up at the first part of a cycle, try not to run other things which are water intensive at the same time. (For example, don't run the washing machine and dishwasher at the same time - put one on a delayed start, don't start the washing machine and then immediately get into the shower).
Secondly, check if your manual recommends a max load size per cycle. A lot of people use the quick wash cycle but they are usually designed for just a small amount of laundry e.g. 2kg. I actually did the saddo thing and weighed a laundry basket full of clothes to see how much I am supposed to fit into each wash!
Lastly check how brand new things smell after being washed - if your clothes have been washed in too little water with too little detergent and/or they have loads of fabric softener build-up, they might benefit from being "stripped" or put through a hot wash or just a couple of really intensive cycles with not many clothes in.
And yes run a maintenance wash every so often. It helps keep the machine running well.