If you do get an acceptance for publication, you might be asked to sign an author agreement/contract with the publisher. Some standard agreements require things such as transferring copyright or prohibiting what you can do with your own work. See Benjamin J. Keele, Advising Faculty on Law Journal Publication Agreements for a brief basic review of terms to consider.
Hosted by Science Commons, you can enter the article information and choose the rights you want to retain and generate a standard addendum on pdf to provide for the publisher's consideration. http://scholars.sciencecommons.org/
Journal publication agreements vary widely, but there are some resources that help authors get an idea of what a journal's standard policy has typically been. While the journal publication agreement itself must always be reviewed, looking at these resources at the time of submission can be helpful, particularly if it is important for you to retain certain rights in your work. Regardless of what a publisher's standard agreement states, you can always try to negotiate different terms. If the publisher is unwilling to budge from its position, you then need to decide how important it is to you to publish in that particular journal.