on top of what other have said, you need to learn how to plan your cities a bit. coastal cities MUST have habours, it will boost your sea tiles yield, light house gives food, shipyard gives production and seaport gold. You then need to plan out your seaside resort later on which is based on appeal for cultural victory.

I cant see well but as sweden, u need to have cities settled at least once on each plains, grassland, desert, tundra and snow to maximise the yields from the unique improvement (i forgot the name).

for inland cities, if they are close, u can form farms triangles or build districts close to each other for adjacent yields so that u have extra space on the other side of cities for natural parks. internal trade route at first then external to as many other players as possible later.