RSS feed submission is really helpful. You can send your updates directly to your subscribers through it but for that you have to get subscribers first, which is not an easy task. You have to make content worth readable and give what your readers want. Know your niche and engage with other users visiting or commenting on your blog. Help them finding solutions to a problem or give them information of the latest things in trend in your particular niche. Be sure you are the first guy to do that. You can also submit your RSS feed to various RSS submission sites so that they easily get index in no point of time.