Just like a room in your home, a garden can be enhanced by a focal point.
Outside is the key to draw the eye and tempt people further into your space and this can be achieved in many different ways.
A large specimen plant or tree can be a good idea, especially if it is quite showy or maybe a bit unusual. Alternatively you can take a quite common variety and remove lower branches to show off a striking bark.
It is probably best to select something with a long length of interest, maybe evergreen or very striking.
A very large container planted up can look very good and be changed to suit the different seasons, always ensuring it looks interesting [Container gardening]. Even a grouping of pots can make an interesting focal point if done in the right way.
You might decide to invest in an ornament, maybe a figurine or animal. They do come in all shapes and sizes, so take the time to find something really special. If need be wait until you find something you fall in love with rather than taking second best, you will only regret it later.
If you prefer to do a bit of recycling it is surprising what can be achieved. What about an old motor car filled worth colorful bedding plants or even old farm machinery brightly painted. Another good idea is to create a type of totem pole effect by concreting old pillars and decorated them.
Whatever you chose be careful where you place it, sometimes a position less obvious makes for an interesting twist.