1. Site it right - Take the time to carefully plan where on your site your garden would be best suited. Consider what plants you are planning on planting in it and what these plants prefer. All day sun? Shade? Etc. Also consider environmental factors such as if this is a herb garden, will you be gathering produce more frequently? If this is the case consider a convenient location at all times of the year for your access.
2 .Follow the sun. This works alongside "Site it right". Once we have established what we are planting, consider where your sun rises and falls in relation to location options. Different plants have different preferences when it comes to light and sun.
3. Water regularly. This is relatively self explanatory, however doing research on what water conditions your plants prefer will guide you and save you the hassle of nursing over or under watered plants back to health.
4. Start with great soil. This again seems self explanatory, however some plants will allow for poorer or more sandy like conditions where others need quality soil from the start and to be topped up with fertilizers regularly to keep your soil quality prime for growth / produce.
5. Consider type of garden beds.