The last bit of advice is to expect visitors. There will be insects, birds and possibly small rodents that frequent your garden. Before you lay down the traps and spray the garden with pesticides, investigate to see if these visitors are actually causing any harm. Most of the time, all this activity indicates a very healthy natural space, you’ve managed to create a space where natural processes can occur. The birds either feed on fruit and insects, as do the rodents. The insects eat each other and they might chew on a leaf or two here and there, but its part of the cycle. Expect to come across spiders in the trees and worms in the soil, and if you are squeamish, put on a pair of gardening gloves, just don’t kill the poor guys, no-one likes and unruly landlord.
I would only recommend organic pesticides if there is a serious problem. With that in mind, when doing your research makes sure you see which pests attack which plants species. Citrus trees in Cape Town are often the victims of multiple pests: scale, whitefly, aphids, just about anything that you can imagine will attack them. These trees require more of a care regiment then most, but if you want life to give you lemons, you need to work for them.