There are countless ways to acquire good job skills, but you will need to decide what kind of job you are hoping to obtain so you know what specific job skills you will need to obtain. Just about all jobs will require you to be organized, punctual, able to handle stress, and able to adapt to different job situations; if you have never worked jobs that require this, you may want to consider volunteering for an organization that will give you such experience. You may also want to consider doing an internship at a company in the field in which you intend to apply.
Not all job skills can be gained simply through education, though many employers are looking for people with some formal education. A high school education may be sufficient for some jobs, but remember that the more competitive the job market gets, the more valuable an education becomes. If possible, attend high school and college courses to further your understanding of the topics relevant to the field in which you want to work. Community college courses are less expensive and can offer you trade classes as well as more traditional subjects like English and math.
Interacting well with people on a regular basis is one of the most important job skills you can obtain. You must learn to interact with all sorts of people, including difficult people and people you do not agree with. Being able to deal with particularly frustrating people without losing your cool is a very appealing trait for employers; you can work on this skill by volunteering, by joining clubs or organizations and participating in those clubs and organizations regularly, and working a part-time job that puts you in contact with people regularly. The skills you will obtain through such jobs will develop as you work, and they will prepare you for better jobs down the road.
If you are in school, be sure to take advantage of study abroad programs, work-study programs, and volunteer opportunities. Not only will these activities help you develop job skills, but they will also look great on a resumé and even help you establish contacts in a particular industry for a future job hunt. Try joining a student organization such as the student newspaper or student government. These activities will help you become more organized, well-spoken, punctual, and able to interact with different types of people.