One of the best things you can do is pick a style and the colors you like and work toward that "look" as you go. In your current rooms I can see elements of farmhouse, traditional and some Mediterranean. If you are not sure what style you want try looking at the different styles in the photos on this web site. There are also some very good articles on what key pieces will get you the style you like such as: "12 Touches to Add Farmhouse Style to Your Dining Room"
Once you have picked a style and the colors you like then you can start switching items out as your budget allows to work toward that look. Paint, light fixtures and a few accessories can be a very budget friendly way to add that style to your rooms. Since your kitchen, dinning room and living room all connect try to use the same style and colors for all of them. Don't fall into the trap of buying items that are "pretty" themselves but not really fitting into the "style" you are trying to create.
Q
Strong Tones Painted in Wimborne White No.239, Green Smoke No.47 | Estate Emulsion; Green Smoke No.47 | Modern Eggshell; India Yellow No.66 | Modern Emulsion & Modern Eggshell Darker tones can give living rooms a magical quality, especially in the evening light. For interest no matter the time of day, try contrasting tones of equal intensity on walls and ceilings, or where one room flows into another.
Q