In additional to selecting the publication type (journal article, conference paper, book or book chapter) for your research, some points to consider are:
Is the publisher reputable?
Do you have co-researchers or co-authors?
Is there any issues relating to the authorship of your publication that you need to consider or resolve?
Is your publication a creative work or a commissioned report?
Does it meet the eligibility criteria for a research output?
Would your research be on interest to a broader audience beyond academia?
Should you publish within both an academic publication and a non-academic publication?
Would your research profile benefit if your selected publication was open access?
Are there any copyright implications relating to the publication of your research output?
How long does the process take from submission to publication?
Check if there is a cost associated with the publishing process.
If you are planning to publish a journal article:
read the aims, purpose, scope sections on the journal's homepage
emailing the journal’s editor with your abstract and enquiring whether your article's subject/topic would be of interest to the journal can assist in the decision making process of where to submit the manuscript
check the acceptance rates for your chosen publication, if difficult to locate, contact the journal’s editor to request sharing the information, alternatively, search Google for the journal name and the phrase "acceptance rate"