The most important thing is to be attentive and vigilant. Make sure to give your plants the proper nutrition, light and water---the healthier the plant, the less likely pests will bother it.
That said, many plants are particularly susceptible to certain pests. These can enter your home (and garden) in many different ways, so it is important to pay special attention to new plants----the change in environment will often stress plants and make them more susceptible. Isolating houseplants to make sure they are bug free before moving them in with your other plants.
We have several different products and care suggestions for each specific insect, so either send us a question on our Contact Us page, or ask us in store. Pests have happened to pretty much all plant parents, so you are not alone. We also have some information online in our Learning Center--link in the top bar menu.
In the greenhouse, we use several techniques to minimize the chance of pests. We make sure to keep plants properly fed and watered, including regular foliar spray feeds. In addition, we regularly spray with a simple soap/water spray solution. We also periodically utilize "beneficial bugs" to fight the pests that attack plants.