Full stack development is the practice of working on both the front-end and back-end of web applications. To become a full stack developer, there are several skills that you need to master. Here are some of the most important ones:

1. Proficiency in multiple programming languages: Full stack developers need to have a good understanding of programming languages such as HTML, CSS, JavaScript, Python, Ruby, and Java.
2. Knowledge of front-end development: A full stack developer needs to have expertise in front-end development frameworks such as Angular, React, and Vue. They should be able to create responsive and interactive user interfaces that are visually appealing.
3. Familiarity with back-end development: A full stack developer should have knowledge of back-end development frameworks such as Node.js, Ruby on Rails, Django, and Flask. They should be able to develop server-side applications, APIs, and databases.
4. Understanding of web development architecture: Full stack developers should be familiar with web development architecture, including concepts such as client-server architecture, model-view-controller (MVC) architecture, and microservices architecture.
5. Database knowledge: A full stack developer should have knowledge of databases such as MySQL, MongoDB, and PostgreSQL. They should be able to design, develop and manage databases.
6. Proficiency in version control: Full stack developers should have a good understanding of version control tools such as Git, SVN, and Mercurial.
7. Problem-solving and critical thinking: Full stack developers should have excellent problem-solving skills and be able to think critically to solve complex problems.
8. Communication and collaboration: Full stack developers need to be able to work well in a team environment and communicate effectively with other developers, designers, and stakeholders.

By mastering these skills, you can become a successful full stack developer and build end-to-end web applications.