1. Not understanding the problem: Many beginners jump into coding without fully understanding the problem they are trying to solve, which can lead to mistakes and confusion.

2. Not planning the solution: Without a clear plan, beginners can easily get lost in the details and end up with a poorly structured solution.

3. Not using comments: Comments are a great way to document your code and make it easier to understand, but many beginners forget to use them.

4. Not testing the code: Many beginners write code without testing it, which can lead to bugs and errors that are difficult to fix later on.

5. Not using proper naming conventions: Not following standard naming conventions for variables, functions, and classes can make code difficult to read and understand.

6. Not understanding the basics of data types and structures: Not understanding the basics of data types and structures can lead to errors and bugs in the code.

7. Not understanding the scope of variables: Not understanding the scope of variables can lead to bugs and unexpected behavior in the code.

8. Not understanding the control flow: Not understanding the control flow of the program can lead to bugs and unexpected behavior.

9. Not understanding the use of libraries and frameworks: Not understanding the use of libraries and frameworks can lead to problems with compatibility and performance.

10. Not understanding how to debug the code: Not understanding how to debug the code can lead to frustration and a lack of progress.

It's important to keep in mind that making mistakes is a natural part of the learning process, and the key is to learn from them and not repeat the same mistakes again. With practice and experience, beginners will become better at identifying and avoiding common coding mistakes.