Posting pictures on your feed is more than simply uploading a picture. Usually it involves many steps, like for examples: Content planning, dressing up, visiting location, taking multiple pictures, selecting favourite ones, edit them, create the content as planned, etc.

Learn with time and grow through experience

Improve photo skills over time:

-Better lighting knowledge

-Better planning and location scouting

-Better poses and angles

-Better camera skills

-Better editing skills

Examples:

https://www.instagram.com/p/CWls5Vyv1xp/

https://www.instagram.com/p/CXKbnilFO9P/

-Learn how to edit and apply filters

Example by 3rd party provider of filter presets:

https://www.instagram.com/p/CWs7pJOg_4O/

Colour-coordinating

Make sure all posts follow the same colour schema (Have a colour, which is repeatedly found in every post)