Sometimes you get kitchens with plain single colour tiles that may be white or some other undesired colour, you can choose to paint these tiles is you prefer, or you can replace them if they are cracked or damaged. Maybe you have moved into a new home and hate the tiles and colour scheme and want something that fits you.
Think about the colour scheme you have in mind and try to get tiles that match that. Whether you are going for a single colour plain tile effect, or a mix of a primary, secondary and tertiary colours to create some type of pattern with the tiles, like a chequered or alternating effect. You should also consider the contrast of the tile colours, and whether those colours actually go well together before you fit them in place, as it’s going to look awful later and going to be a costly mistake later.
Whatever style you choose, don’t use any-more than 3 colours and find the balance that suits you, matches your theme and contrasts well.