Conferences are a good start - they give a deadline which is publically known, you get feedback at the event and afterwards, and the proceedings are often published. If you are working towards writing a book, then go to the publishers for advice. As a commercial publisher, Philip is not particularly keen just to publish material for the RAE - it has just added a layer of chaos and made human relationships more frantic. The key to getting published is to realise that different journals have different requirements, and it pays to discuss your project widely at first. Don't keep your ideas to yourself and don't work for ages before making any of it public.
All feedback is valuable.
If you are approaching a publisher and have not yet established a contact, write to the MD and the letter will be passed to the best person. Good people to contact early are the editors of series. The other good people to contact are the editors of journals - find out what they are intending to publish and the direction they intend for their journal. In both cases you can do much of the research into which is the most appropriate before making the contact - don't use the scattergun approach, it is only irritating and ineffective. Sometimes research can be too parochial, whereas for publication you should be keeping to a broad readership.