Students who are not EU passport holders are rather limited in the employment they can legally do in the Czech Republic. To pay for your studies with a part-time job is not really feasible. A typical hourly rate for student jobs is about CZK 100 for basic administrative work. You should also take into consideration the fact that your studies alone will require a considerable amount of your time.
If you are a citizen from a non-EU country and you want to work while you study, it is possible, but as you are in the Czech Republic on a study visa, paid work cannot be your primary occupation during your stay. Remember, you are here for study purposes.
Full-time students from a non-EU country at a university registered with the Ministry of Education, Youth and Sports only need to be registered at the Public Employment Office (Úřad Práce). This registration is made by the employer.
You can ask for legal advice, free of charge, in one of the centres in Prague:
Where to find a job if you don’t speak Czech?
When looking for a job, try asking your professors first – they may be looking for some personal assistance or even for some staff for their scientific projects. Asking your friends and other private students is obviously the easiest way. You may also try the conventional way, i.e. looking for a job through job portals.
There are some portals, where foreigners can find job offers and vacancies in the Czech Republic. (Jobs, Expats, EURES, Employment Offices in the Czech Republic database).
You can also register your CV on the main page of job seekers in Czech Republic and present your profile for your prospective employer.
Note that in most companies, even when the official working language is English, Czech language knowledge is essential for basic communication with your colleagues.