Use the Ulrichs Periodical Directory to identify indexes that might be appropriate to submit your journal to for consideration/inclusion.
To be recognized as an authoritative, high-quality source of information, a journal must be widely available. Indexing and abstracting services facilitate the broadest dissemination of information by pointing researchers to articles that are relevant to the field. Once a journal is launched and has a track record of timely publication and solid content, it is appropriate to contact indexing and abstracting services for consideration.
The decision to include a journal is based on several factors, most importantly a great deal of high quality content, with much more in the pipeline, that is produced on schedule. Please note that electronic journals may be seen as less attractive by some services, although this is beginning to change.
Once on firm ground with respect to the quantity/quality/schedule issue, it is time to approach one or more indexing and abstracting services. Though each discipline may have indexing and abstracting services specific to the field, there are several all-around well-known, well-regarded services.
Directory of Open Access Journals: How-To Guide for Library Publishers: Directory of Open Access Journals Application, by the The Library Publishing Coalition.
The large database vendors below often include journals in multiple databases that they own; a contract with one of these vendors can help place your journal in both discipline-specific and multi-disciplinary databases and indices.