Trademark applicants represented by attorneys are 50% more likely to get through the registration process than those that who go it alone. However, it doesn't hurt to do some early leg-work yourself.
You can search for identical trademarks using the trademark office's Trademark Electronic Search System (TESS).
TESS has an extremely steep learning curve and if you don't invest the time in learning both how to properly query the database and learn enough trademark law to interpret the results, it's highly likely that you will miss trademarks that will block the registration of your own.