Optimization of .NET application seems complex and tied full task, but don’t hurry up with conclusions. Let’s look on several cases from real projects. For this we: look under the hood of an application from a real project; define the metric for optimization; choose the necessary tools; find bottlenecks /memory leaks and best practice to resolve them. We'll improve the application step by step and we’ll what with simple analysis and simple best practice we can significantly reduce total resources usage.