Eat real food.
This is a simple reminder to keep telling yourself and it's really the crux of eating clean. In most cases, if you are eating real food you are eating clean.
As much as possible, try to eat produce and foods that are in season. An easy way to go about this is to base your meals on ayurvedic philosophy. For instance, this list tells you which foods to favor and how they will support your body.
Use tech to monitor your intake.
While calorie counting may not be entirely relevant, it can be helpful to use an app like MyFitnessPal to track your macros. The app allows you to input your ratio goals (i.e. 30% protein, 30% fat, 40% carbs) and will show your progress in graph form.
Determine your allergies.
Undergoing an elimination diet to determine your food allergies is an excellent way to improve your diet and body function.
Subscribe to the 80/20 theory.
In order to avoid deprivation, which is certainly not going to help matters when it comes to maintaining a healthy lifestyle, I like to use the 80/20 rule. This can be customized to fit your personal goals, so it could be as simple as eating healthy, whole foods 80% of the time and treating yourself 20% of the time or as specific as eating vegan 80% of the time.