When evaluating a journal:
visit the website,
research scholars who have published with that journal,
research the publisher itself, and
most importantly, talk to colleagues.
CONSIDER THESE FIVE INDICATORS:
1. Do you or your colleagues know the journal?
Have you read articles in that journal before?
2. Can you easily identify and contact the publisher?
Is the publisher's name clearly displayed on the website and do they provide complete contact information: email, street address, working phone number?
3. Does the journal have an International Standard Serial Number (ISSN)?
The ISSN is a unique eight-digit number that identifies each journal-title. In many countries, an ISSN is mandatory for all publications subject to the legal deposit.
4. Does the website list any fees which authors may be charged for publishing their article?
Does the journal site explain what these fees are for and when they will be
charged?
5. Is the journal a member of an industry initiative or trade association?
Do they belong to the Committee on Publication Ethics (COPE)? - 7,000 members
If it's published by a professional society, do they belong to ALPSP (Association of Learned & Professional Society Publishers)? - 10,000 members
For example The InternationalCommittee of Medical Journal Editors (ICMJE) provides Recommendations for the Conduct, Reporting, Editing and Publication of Scholarly Work in Medical Journals.
Also, consider these if it's an Open Access Journal:
Is it listed in the Directory of Open Access Journals (DOAJ)?
The DOAJ vets journals before listing them. However, there is a significant backlog of journals waiting to be listed, and not all legitimate open access journals are listed in the directory. There are currently more than 11,000 journals listed.
Is the publisher a member of the Open Access Scholarly Publishers Association (OASPA)
Many of the largest open-access publishers are members of the OASPA, though there are legitimate open-access publishers that do not belong.
The more ties to well-known organizations and the more a journal follows best practices, the more likely it is to be a legitimate operation.