Gentle curves, soft flowing lines, billowing rivers of flowers, grasses and trees that move with the wind will all help enhance the smooth and steady flow of chi. Straight lines are not conducive to good chi, speeding up the flow too much that it leaks, leaving you with a cold, unfriendly feeling. If you have straight hedges, avenues of trees or pathways, you can redress the energy balance by softening the edges of a path, or by adding curved beds of planting under straight avenues of trees. Regular shaped gardens are more auspicious than, for example, triangular ones. If you do find yourself with a triangular plot (and you are reading this and thinking you will need to move out at once!) then a good design solution is to soften and disguise the angular nature of the site boundaries. A simple arc or sweep of planting can hide a pointed corner and would instantly help.
A good starting point is to apply some simple good housekeeping rules to your garden. This would include fixing or recycling broken pots and other damaged items, cleaning garden furniture and water features, and generally keeping the garden tidy and maintained.