If you are a student from EU/EEA countries and Switzerland you do not need an employment permit, Employee Card or Blue Card to be employed on the territory of the Czech Republic. You can enjoy the same legal status as citizens of the Czech Republic.
In case you are a student coming from a third country, enrolled in a full-time study programme at any Czech university or language institute accredited by the Czech Ministry of Education, Youth and Sports (MEYS) you do not need an employment permit (official source)
Third-country students who are exchange students or study in a distance form of studies are allowed to work without an employment permit too, but only if they are up to the age of 26 and their performance of work does not exceed 7 consecutive calendar days or a total of 30 days within a calendar year.
Please be aware that, the purpose of your stay as specified on your long-term visa or residence permit has to correspond to your actual activites. In other words, if you came here to study, your workload cannot affect your studies. Although there is no legal limit, we recommend our full-time students to work about 20 hours/week. Visit the Prague for all website for further information.
Probably the easiest way to find a job is to visit the biggest job portal in the Czech Republic: jobs.cz. One should also keep an eye on the job postings offered at the website of the respective faculty. Useful information regarding job opportunities in Prague is also available on the website of Study in Prague and Study in the Czech Republic. Further, various expats websites and Facebook groups are another useful source. If needed, our Carolina Centre also offers career counselling services in cooperation with the Centre for Integration of Foreigners.