The first thing is to tell us how you would like to use the space. Is it something to look at, a space to relax in on your own or with family, friends, entertaining, dining al fresco?

The concrete or breeze blocks supporting the fence in the lower shot indicate the garden next door or whatever is on the other side is higher, indicating a retaining wall?

So in line with designing how to create your side for how you wish to use it, it would be as well to disguise that. Perhaps a raised bed, or to incorporate some terracing idea so that end is higher? It looks to be too far away from the door for the dining area unless you incorporate a cooking facility. But if that area is the garden's sunspot then at least some hard standing for seating, whether patio or deck.

I'm deliberately ignoring the manhole in the middle for now as that can be dealt with when we know what it is to fit in with.

If you are keeping the gravel, then work with what you have a create a gravel garden. Look at Beth Chatto's garden near Colchester for inspiration. I'm sending you a photo or two of recent jobs we have completed. It may help?

Try our pallet seats they can add a nice seating area to your Garden also with nice bright colours.

Subject to your needs for using the space as Freshscaped Ltd. pointed out there 2 major pointers which are important in such as small space.

Firstly a small space tends to be dominated by the boundaries so improving or hiding them is essential to a really good result. Climbing plants on trellis are a fairly quick way of covering them but the faster plants grow the more chance there is that they will get out of control. That's why I very often create bespoke trelliswork as an attractive feature whilst more controllable plants get established.

Secondly you really need to have some vertical features, such as sculpture, obelisks, multi-stem trees or quite open (or transparent as designers will say) planting. Without vertical accents your eye will always be drawn straight to the boundaries without registering depth and so the space continues to feel small. The more can include verticals which allow you to look on, through and past them, the more you will perceive depth.

There are many ways to make a small space feel bigger but these two are probably the strongest and most universally applicable to a typical size of garden.