Similar marks and similar services? We can't predict how a trademark examiner will rule in your case but we can tell you about the standards that will be applied. The examiner will try to determine whether consumers are likely to be confused by the two marks. Here's how likelihood of confusion is determined. The less "related" the goods, the less chance for confusion -- for example, SHELL as a trademark for flatware is not likely to be confused with SHELL as a trademark for liquified petroleum gas.
The zone of expansion. The examiner will also reject an application if the second user's goods are within the first user's zone of natural expansion. For example, a famous seller of wine such as Gallo might be likely to expand into the sales of cheese. Of course, the examiner's decision is dependent on the similarity of the marks and the fame and popularity of the first user. To get a good idea of how the USPTO rules in these matters, we recommend you search The TTABlog where these battles are regularly reported. Type "related goods" into the search box at the blog.