I would start by picking a large beautiful found or octagonal rug. I would add drapery panels between the windows that complement the rug. I would have a large buffet in a wood similar to your trim color. this space needs a large dining table and perhaps a tall plant or two.

Can you show the adjoining kitchen. The table looks small in the space.

This article might be useful? http://aproposconservatories.co.uk/2017/07/how-to-furnish-your-conservatory/