Narrow garden beds
There are many low-growing plants that could be chosen, but the real problem is finding taller plants which provide some interest at highter levels and help disguise unattractive fences.
For a tropical-look garden, consider
As an understory:
(variegated form is available whichis more decorative and white will help brighten up the space)
Vines and narrow hedges
In situations where a good amount of sun can reach from top to botton (e.g a narrow north-facing garden adjoining a driveway) climbers trained on a trllis or certain dense shrubs maintained as a narrow hege might be an option. In a narrow side yard, however, there will be a tendancy for foliage only at the top, leaving unattractive leafless branches at the base.
Whether growing as feature specimens in tight spaces or as a narrow hedge, selecting a species which is naturally narrow (or "fastigate") makes more sense than trying to force an ordinary shrub into the space by pruning. It will be less work and probably look better too.
Many people admire the fastigate cypress pines commonly called "pencil pines", but they are less reliable in the hot and humid parts of Queensland than in cooler and drier parts (Conifers).
A tropical tree species which is exceptionally narrow is the Indian Mast Tree, Polyalthia longifolia. Until recently tis species was relatively unknown in Australian, but it is gradually becoming more widely available. More information; Polyalthia
When selecting a hedge species, it is wise to do some research into not only species, but which variteies within a species might have the most narrow and compact habit. Callistemon viminalis 'CV01' is an example. Over time, we might expect to see more such varieties developed from popular garden shrubs.
Ilex crenata 'Sky Pencil' - see Shrubs
Mini-gardens with pots
If the area is not much visited from the outside, but present unattractive views from inside the house, efforts can be concentrated immediately ourtside the window. Large tubs and planter boxes mean the area can be improved instantly with larger plants. The conatiners themselves give a certain amount of instant height. Both the need for digging and bad soil conditions can be circumvented by growing in pots. However, the regular watering required will mean extra work, unless some automatic watering system can be installed.
Plant selection become wider too. More vigorous species of shrubs, palms, bamboos or ornamental grasses than you would risk planting in the groundcan be tried as they will be contained by the pot (take care not to let them take root through the pot holes). If not successful, the plant can be relocated elsewhere and something else tried in the pot.
Pots can also be moved for painting and other maintenance. Paving, gravel or a low-maintence groundcover will eliminate need for mowing.
Pots can also accomodate small trellis or totem poles to train climbers or semi-climbers like Mandevilla
A Utility area
Given homes will need to allocate space somewhere for storage of rubbish bins and clothes drying (consider foldable racks or retractable lines), all or part of one side yard might be given over to this and other practical functions (worm farm, propagation area, parking bicycles etc). If there is a side door from a kitchen or laundry, this is the obvious spot for a utility area.
They can be screened from the back and front by fences, trellis or strategic planting of a shrub or two. Paving or gravel will elminate the need for mowing and make a better surface for walking on in wet weather.