Democrats have an incredibly easy opportunity right now, just like in 2020 and 2024. They could simply point to all the bad stuff the Republicans have done and promise to do better things. The Dems should be winning by outstanding margins by promising very simple things, like not shooting immigrants or making groceries cheaper. Instead, the Dems promise nothing and as a result, what should be really easy races become down to the wire nail biters.
The Democrat party simply needs to follow the playbook of the most successful Democrat in history, FDR. Promise progressive policies and then actively work towards those policies and you get elected so often they gotta change the rules to stop you from getting re-elected. We can see this with the most popular modern Dem president Obama. He did half the equation, promise progressive change, and even though he didn't follow through, dude got elected twice and is still a household name in the Dem party. Clinton, Biden, and Kamala weren't even willing to lie about enacting positive changes and Biden only won because Trump's COVID policies killed over a million people. Even then, Biden won by a tiny margin when, again, he should have won by an incredible margin.
I agree with the sentiment that voting is very important, so it's vital to come up with ways increase voter turnout. In an ideal society, everyone would make informed voting decisions, but we don't live in that world. We've seen from recent races that people are coming out in droves to vote for candidates with progressive policies with primary races having higher turnout than even general presidential elections. The key takeaway from this summer seems to be that progressive policies fuel voter turnout, especially amongst younger voters, so the Democratic Party should lean further in that direction.