Take a look at these tips for creating Roux:
1. Begin a roux by stirring together the flour and cooking oil, as shown. Then cook for 5 minutes over medium-high heat.
2. Reduce the heat to medium so you can better control the cooking. For a light roux, heat about 10 minutes more. Stop cooking when your roux is reddish brown, as shown. Use this mildly flavored roux for fish and seafood dishes.
3. For a dark roux, cook on medium about 15 minutes. Here's what your roux should look like. Use this darker version for more robust meat and poultry dishes.