Twitter once provided RSS feeds for all Twitter accounts. They no longer provide this service. However, third parties can create RSS feeds from the content of Twitter accounts. BazQux has done this for my daily tip accounts, so you can subscribe to any of my accounts via RSS using the feeds linked to below.
If you would like to subscribe to more Twitter accounts via RSS, you could subscribe to the BazQux service and create a custom RSS feed for whatever Twitter, Google+, or Facebook accounts you’d like to follow.