Drink plenty of fluids and keep piling on the sunblock. Wear a hat. Insects No-one likes too many creepy crawlies and you can keep yourself safe from most by liberally applying insect repellent. Mosquitoes are active mostly by night and most lodges have either air conditioning, fans or bed nets to keep them away. Wearing long-sleeved clothes and pans will also protect you against flies and tsetse flies wherever they occur.
Most people tend to worry far more about the snakes that is realistic.
Though they are common throughout Africa, they tend to avoid people where possible and few people coming on safari actually see a snake. If walking at night, use a flash light. Campers and hikers are more likely to come across them if they overturn rocks or walk through heavy shrubbery. If you do encounter a snake, back off. It will not attack unless it is provoked.