When I had my small kitchen re-done, I first listed exactly what it was important for me to have in there. I also had the door to the kitchen changed to a sliding one, which did free up space.
Had lots of alterations to plumbing and electricity. Moved my one and half sink from along a side wall to go under the window. Had the electricity for oven changed to other side of that door. Previously it had been just as you came into the kitchen, now my freestanding fridge/freezer stands there and my double oven unit tucked away in the opposite corner.
I had always wanted and now have a full height pull out larder unit. ALso a small under the counter pull out unit in a narrow space, keeps all my condiments and spices, etc in easy to get to area. Have those wonderful kidney units fitted for corner cabinets, they take so much and all so easily accessible.
Have kept my freestanding washing machine and narrow dishwasher. Combi=microwave is in the space for the second oven in unit. (Tumble dryer is kept in spare bedroom). Good sized drawers under Induction hobs for cutlery and pots and pans, etc, plus one other set of drawers.
I think the thing to do is two-fold.
1. Make a list of things you must have and would like in the kitchen, with sizes where known.
2. Make an accurate to size plan of your kitchen showing window, door, boiler. Have a few copies of this and then go round kitchen showrooms with this,so that the salesmen there can start to work out how to design your kitchen. Do remember sinks, etc can be moved.