Be sure the work if original. Plagiarism or "citations" of non-public works may have heavy consequences. Don't be too postmodern in legal matters. Putting your name under the music of somebody else is very bad. Everybody hates pirats, even their mother. If you want easy money, you'd better to commit some hold-up. If you want glory, you have to be original.
Be sure the work is free. If you already have a publishing contract with another publisher, you can't submit us the work. Even if the publisher doesn't exist no more. In this case, a liquidator has maybe sold the publishing contract to another publisher. The situation must be absolutely clear.
Take care to the 'hidden' publishing contracts. Maybe a production contract
(for a CD, a video, a picture) incude a publishing contract for the work.
Check this carefully.
Do not forget the authors, libraittists, translators, arrangors, orchestrators etc. Those guys are reals and, if not dead for 70 years, their work is subject to copyright. Contact them before to be sure we shall not have problems.
Be sure the music is OK. Read and re-read again your work before sending it. The most problems we encounter are :
unconsistent alterations
unconsistent rythmic alignments
missing pages
unlabelled staves (which instrument plays that?)
Be sure it is finished. If not, finish it.
If yes, send it... but please don't add or delete complete systems during
the publishing process. Well, it's normal to change some accents, to add
some slurs or to correct some chords. But do not rewrite your music after
having submit it to the publisher.
If we choose to publish this work, all these problems have to be fixed.
So, fix them before sending your work. We will be grateful for your prevenance.