Here are a few little tips that I have come across that may be helpful. I will add to these as I discover more that may be of use to you.
- Mustard planted between rows of vegetables may help to keep slugs and snails away
- Plant strawberries with garlic or onions to prevent fungal diseases in strawberries
- Plant nasturtiums around fruit trees to help to prevent aphid infestation
- Plant dill between rows of beans