How much are you willing to spend on it and what's your climate like?

Replacing the low roof with a gabled or hipped roof would make it feel much more open and spacious. Also an exposed timber framed roof with timber decking over the concrete would look really good but does depend on the style you like.

A cheaper option is to replace all or some of the sheeting with clear sheets to let in more light and paint the steel framing. I think a black frame with clear sheets would look good

Hi Cheri, if you are looking for cheaper options than playing with the roof, maybe look at:

Concrete paint or tiles for the flooring

Coating the retaining wall in stone or timber

Planting out the bottom of the retaining wall with shade tolerant plants

use bright colours in your furniture and dressing

The trees don't look very big - i'd get another quote. The fence colour is ok - its light and 'background' enough - just needs smaller plants infront

I quite like the look of the dark trunks with light backdrop. Agree with adding in some low plants.

Agree with others re adding some clear roof sheets for light but they can get hot depending on the aspect.

It would be a shame to get rid of the trees so maybe maybe a budget option could be some bamboo blinds attached to the side of the roof might help stop some of the mess. Add some colourful pot plants & string up some nice outdoor lights, a couple of outdoor rugs...do you have a theme or style in mind?

What will the area be used for? With some paving paint on the concrete & some nice comfy outdoor furniture it could be transformed & inspire you to use it.