If you don't have a lot of experience with this kind of decision, you should first consult with your supervisor, mentor and/or other members of your research group. If you're trying to do this without some form of mentorship, unfortunately you're probably not in a position to publish anything if you don't know where your work should be published.
For what it's worth, when writing a scientific paper, it's usually best to decide which journal you're going to target for publication early on. This helps with decisions with respect to format, word count and the background of the intended audience. These can always be changed of course, but it saves a lot of time if you start out with the template you want.
One way to make this decision is to look back through your references. Usually the best journal to target is the one that you've referenced the most, since that's where the most relevant material comes from, and therefore is likely going to have the most appropriate audience for your work. Other options include the ones you read the most. Go through the bookmarks in your web browser and your short-list should likely include those journals that you read every month. (If you're not reading journals on a regular basis, that also suggests not ready to publish in one.)