In practice or in theory?
In theory, the Federal Government abides by the constitution and deals with things outside of, or superior to, the individual states. ie. Minting money, the military, roads, US Postal Service, war, international affairs, felony crimes, taxation, etc.
Individual states would enforce the minimum standards set by the federal powers and can be more stringent if necessary. States *used* to control the Military Reserve units. The POTUS and Feds had to request the use of reservists for operations/actions. (I believe that changed sometime after 9/11, but I don't recall when).
In theory, it's easier to change things at the local and state levels. You can move to another town or state with relative ease, if another area has politics more to your liking.
In practice, (at least, based on my opinion) the Federal Government has substantially more power than the founders ever intended, and as a country we're wrapped up in way more international affairs than we should be. The State Governments are dependent upon the feds for financial support, funding special projects, bail outs, subsidies, etc....(I'm sure there's more, but lets keep this fairly short).
Realistically, most people only care about the federal issues portrayed on the daily news. I'd love to blame this on the media but it's also due to people being lazy -- myself included. I couldn't even tell you who the current City Mayor is, nor name most of the city politicians or state representatives. It doesn't usually make headlines, so we ignore it. Yet every election cycle, we hear about the presidential candidates positions on taxes, guns, abortion, religion, "equal rights", and basically the same talking points that never have any real bearing once the candidate is in office. We eat that shit up. It's entertainment & drama.