I am having cold and have been taking cold and flu medicines available otc. No improvement &the mucus from my nose is red now. What should I do? Thanks

Depends. Most colds are viral in origin and will start to improve in 3-7 days. If your symptoms are increasing in severity after 7-10 days you may have a bacterial infection in the sinuses that may require antibiotics. If less than seven days continue with otc medicines and stay hydrated. Red mucous may represent some blood from frequent nose blowing.
Fluids and rest. The answer depends on how long this has been going on. Red, assuming it is blood, suggests irritation in your nose. A nasal saline spray might help soothe it. If there is no fever and symptoms are less than ten days; fluids, rest and symptomatic treatment is probably the best thing you can do. If you have fever more that three days, you are short of air or fever recurs you should see a doctor.