Healthy plants can withstand cold temperatures much better than those that are neglected. Remember to water deeply during dry spells. Be careful to follow watering restrictions. By mulching tender plants you can help trap the heat in the soil. When there is a predicted frost, cover plants with sheets, blankets, newspapers, cardboard boxes or any other suitable materials. This covering should not be left on more than two or three days even if you have to recover them later. If you use plastic, it must be removed the next morning.
You can't do much to protect tropical plants in the landscape from being damaged or killed by a hard freeze. Covering only protects against frost and possibly a light freeze. Some people erect tall, plastic covered structures and hang lightbulbs in an attempt to keep the area warm. Potted plants can be moved indoors, to a garage or shed for temporary protection. After potted plants are moved back out, be sure to check the soil for dryness.
You may be tempted to prune cold-damaged plants, but severe pruning on woody plants should be delayed until new growth appears in the spring. Herbaceous plants (those with green stems) that tend to rot after a freeze can be cut back to the ground to try to save the root system.
Information from Carol Suggs and Theresa Badurek of the Pinellas County Extension Service and from the Hillsborough County Extension Gardening Almanac. Go to the extension websites at pinellascountyextension.org and hillsborough.extension.ufl.edu.