Generally, I don't bother trying to make "casual" attire evening appropriate. I put casual in quotes because I'm talking about countryish traditional clothing, rather than, say, jeans or rumpled khakis and a sweater or casual shirt (which I'll wear to dinner only if I'm rolling into a casual establishment after a casual day).
If I'm wearing a suit, say, or getting dressed in a navy blazer and gray trousers, I'll wear black shoes, a white shirt, and a "sharper" silk tie than I might if I were getting dressed in the same formality for something at 11:30 AM. I might wear very dark brown shoes. If those rigs would be too formal, then I'd be quite content to wear something like a relatively dark sportcoat, light blue shirt, gray slacks, and dark brown shoes, with a tie that strikes my fancy. Slightly darker than my normal attire, and at the dressy end of things for me.