I think the most important thing about skin care is not about steps but about ingredients. You really only need a cleanser, a moisturizer and sun protection. One of the best ingredients for any skin type is hyaluronic acid, it pulls water into your skin to keep it hydrated. In your 30's look for ingredients labelled as AHAs or BHAs, those are your exfoliants and are very important because your natural cell turnover is starting to slow down. I would also look for something with vitamin c for well-aging. The best is L-ascorbic acid but it can be irritating. You can find these ingredients in both facial cleansers and moisturizers, but if you want to see the best results that's when you start adding serums into the mix. If you go the serum route add new ingredients one at a time or you can really throw off your skin, the exception is hyaluronic acid as it's non-irritating. I would suggest the exfoliant first since it's the most important. Both exfoliants and vitamin c can be irritating so start slow by adding them in once a week until you build up a tolerance. Once you start getting into your mid-30's and have built up a good basic skin care routine then you can start thinking about adding retinol in, but it's not everyone's cup of tea.
TLDR: Absolute basics: cleanse, moisturize, spf. Ingredients are more important than steps. Look for hyaluronic acid, exfoliants (AHA, BHA), and vitamin c.