Predatory journals are rarely indexed in Scopus and very rarely indexed in ISI ( SCI, SCIE, SSCI and AHCI) and never published by major publishers ( Elsevier, Springer, Taylor & Francis, Wiley-Blackwell, Sage, Emerald, Macmillan, Edward, Degryter, Indersiene, World Scientific Publishing,..) and by uinversities or public institutions. But all predatory journals are always published by small, newly established companies or invididuals.

I think the best way is to go to the journal website and check where all the journal is being indexed. It would be better to avoid journals which are not indexed in Scopus, SCI, SCI-E etc. I have also noticed some journals having impact factor just months after they have commenced publishing. It is better to avoid these journals too as the impact factor they have mentioned is not issued by Thomson-Reuters.

Issac - good response from Hari. It's becoming quite easy to recognise the predatory journals and editors. The first warning sign is unsolicited emails, particularly if you are not that established in your discipline field. The intention is to lure inexperienced researchers with the promise of early publication and to 'positive stroke' the researcher to believe that they are important in the field. Often a 'bogus' journal will start the invitation by stating something like 'We have noted your expertise and excellent previous journal article entitled...'. I always immediately delete those. it's just as a result of some 'random' database search. The second warning sign is 'have you ever heard of the journal before (beware of journals that almost exactly copy the title of established journals) and, if so, is it an established one with a reputation for good quality copy?'. The likely answer is 'no'.

Here is the complete list of Journals according the category

http://science.thomsonreuters.com/cgi-bin/jrnlst/jloptions.cgi?PC=K

To avoid such Journals one should always check for the SCI (or atleast SCI expanded) indexing of the journal which is a valid measure of reputation. You can search about the Journal through its ISSN no. at the link given below

http://ip-science.thomsonreuters.com/mjl/

Check Beall’s list of potential, possible, or probable predatory scholarly open-access publishers http://scholarlyoa.com/publishers/

Perhaps more useful though would be a list of good open access journals. Directory of Open Access Journals (DOAJ) list journals but I am not sure if it has any quality check of them http://www.doaj.org/

Check the top answers on the discussion thread below (link attached).

The lightest, most elegant solution is common sense and objective and critical analysis (as we are trained to do). If knowledge, resource or time prevents that strategy, remember that Gold Open Access (author charges for publication) are not the only way to harvest the benefits.

Green Open Access has EC-funded e-infrastructure (www.openaire.eu and www.zenodo.org) and is supported by funders. Most of all, it costs you nothing! Well, not true. It costs you 10 min per article (compared to the 18 months it takes to research & write one).

https://www.researchgate.net/post/Why_do_authors_publish_in_predatory_open_access_journals?_sg=o9Bx2ydvj9nK3Qx51arbtH73dq2f2iCsqpVA6wgjHEBmCJJXinvpo5kvM4Nj19Fs_pw338Zpkl99QUGqiAvQ4BlNmPATb%2BcJR21c3GO9hmBuMOMkFJlo6Z%2BbLyTDE5HAF_Am2Y%2BsjGieyfGlzETn640yFISSK1YBDDuy6RHWZj%2B1vQF6H5L4cHI3hnz4xiC36R

I often teach my students about how to avoid predatory journals. 

1. Perhaps the best strategy is  to check whether the name of the journal is Jeffery Beal's list of the predatory journals 

http://scholarlyoa.com/2014/01/02/list-of-predatory-publishers-2014/

2. Check whether that journal is indexed in PubMed. Find the name of the journal in NLM catalog. http://www.ncbi.nlm.nih.gov/nlmcatalog/journals 

3. Check the impact factors of the journal. Be careful with this, because there are emerging fake metrics for predatory journals like GIF(Global Impact Factors). 

Don't use this bogus impact factor metrics from http://globalimpactfactor.com/ . This is not true. 

I think cite factor is also another fake metrics for open access. I don't recommend. journals http://www.citefactor.org/journal-impact-factor-list-2014.html. 

4. Find the journal ranking in SCImago http://www.scimagojr.com/

5. Check Jocalyn Clark: How to avoid predatory journals—a five point plan

http://blogs.bmj.com/bmj/2015/01/19/jocalyn-clark-how-to-avoid-predatory-journals-a-five-point-plan/ 

6. Ask your professor. 

Predatory journals are rarely indexed in Scopus and very rarely indexed in ISI ( SCI, SCIE, SSCI and AHCI) and never published by major publishers ( Elsevier, Springer, Taylor & Francis, Wiley-Blackwell, Sage, Emerald, Macmillan, Edward, Degryter, Indersiene, World Scientific Publishing,..) and by uinversities or public institutions. But all predatory journals are always published by small, newly established companies or invididuals.

A checklist to identify reputable publishers

● Check that the publisher provides full, verifiable contact information, including address, on the journal site. Be cautious of those that

provide only web contact forms.

● Check that a journal’s editorial board lists recognized experts with full affiliations. Contact some of them and ask about their experience with the journal or publisher.

● Check that the journal prominently displays its policy for author fees.

● Be wary of e-mail invitations to submit to journals or to become editorial board members.

● Read some of the journal’s published articles and assess their quality. Contact past authors to ask about their experience.

● Check that a journal’s peer-review process is clearly described and try to confirm that a claimed impact factor is correct.

● Find out whether the journal is a member of an industry association that vets its members, such as the Directory of Open Access Journals

(www.doaj.org) or the Open Access Scholarly Publishers Association (www.oaspa.org).

● Use common sense, as you would when shopping online: if something looks fishy, proceed with caution.