Hello!
Kitchen designer here 😀
Some of my top tips for making choices I tend to give customers are:
-Think about things you have in your kitchen that you know you want still in your next one= things you like.
-Think about things you don't have in your current kitchen that you would love to have.
-Things you definitely do not want.
Things I advise to have if you can:
-Pan drawers: they are deep, super handy for storing pots, pans, jars, and making accessing things very easy and hassle free.
-Having the oven in a tall unit: not having to bend down to get things in and out of the oven is a luxury and your back will 100% thank you. Not everyone has the space for this but I highly recommend this.
-A good extractor. Don't cheap out on having good extraction in your kitchen, it'll make sure you control smells and excess moisture and reduce potential for mould in the kitchen. There are some very good brands like Bora who have the extractor built into the hob. They aren't cheap, but they work really well, and they are very well built.
-Quartz worktops: they come with around 25y warranty, are durable, they look lovely and they don't get water damaged over time.
-Toughened glass splashback instead ot tiles, this way you won't have mould or dirt accumulating between the tiles and your kitchen will look new and spotless for a lot longer.
-Corner carousels: makes it a lot easier to access the back of the cabinet storage, and remember all the things you have in it. Getting to the back of a corner unit can be such a hassle!
And my advice (biased, as I work for an independent kitchen shop, but I have worked for bigger retailers prior to that for many years) do not go with a big kitchen retailer like Howdens, Wren, Magnet... they minute they take your money, they don't care. Quality is lower, and will last you less time.
Go with a good local independent kitchen shop. They will bend over backwards to help you, advise you, make sure the fitting is spotless, and they will really care about making you happy because customer service and word of mouth is what makes them survive. And also, the quality products they sell is way superior and will last you longer. I advise to go with german brands if you can.
I hope this is helpful!