A CEO once told me that he would only hire a person if he thought that he would enjoy the time spent with that person despite being stuck at an airport with them waiting to board an indefinitely delayed flight. Despite the exaggeration, I've always imagined the equivalent scenario as whether engineers would want to spend hours with a PM in a war room or a bug bash.
Be an engaged partner. Be in the trenches with them. Work hard or harder. Follow-up and follow-through on your stuff. Be transparent about the real business context, the one they may not have heard. Tell them about what you are up against. Bounce ideas off of them, ask about options, be curious. Be their ally, advocate, or sounding board when needed but not blindly. Don't just toss a problem over the wall. Write a technical PRD vs a one-pager. If they are "not delivering" don't just report it as late in a status meeting. Meet proactively- ask what can you do to help them do their part. There could be a zillion other reasons- they are working on something else that's more important, or even less important but they didn't know otherwise, they don't know how to "fix it" yet, or they are dealing with personal issues, etc. Admit your mistakes and help them recover from any of theirs. This does not mean sweeping real issues under the rug. Address things that cause real damage head on privately or less privately as needed.
By now you may have noticed that none of my answer contains anything about having more technical knowledge. It is also true that getting increasingly more technical will always help. But it won't impress or influence. Being real and human is more impressive these days; it will build trust, and trust paves the path to true influence, one that cannot be confused with coming from title or power.