How can I build up more influence in an org?

The advice above is spot-on, and to add to this, I heavily recommend this career advice about leading without authority from an E6 at Meta.

Once you get to E5, relationship-building is super important. Work with your manager to identify key stakeholders that are important to you and your projects and spend time cultivating their trust and getting to know them, their worldview, and their incentives. Lack of social capital generally holds you back once you're at this level, and the tricky part is that these "trust seeds" take a while to grow (unless you have Speech 100). You should do all this as soon as you join a team, but if you've already been on a team for a while, better late than never!

In some cases, I'm unable to get my idea to land, and another software engineer will get something similar approved later on.

Some ideas on how to remedy this, so it doesn't happen again:

• Identify key decision makers proactively and make them your allies
• Pitch your case in a more concise way that's easier to understand
• Use data to back up your idea (this is really effective at Meta)
• Work backwards from core principles in your team/org and clearly explain how your proposal champions these principles
• Propose 2+ approaches when you're pitching - People understand things in terms of deltas. If you can show this worse option alongside yours, it makes it easier to understand why your chosen approach is good
• Learn from the engineer that succeeded with your idea! What did they do differently? It's likely one of the above.

• Being heard is hard if you have not gained enough trust from the team.
• Clear and concise communication of the goal and what problem they solve is key. (Elevator pitch, TLDR, etc)
• Don't try to push your solutions as the best solution. Don't bound yourself to them, seek and incorporate feedback.
• Be proactive in your team and get them involved into solving the problem you've identified. Recognize those who help you.

And finally, understand that life is not a fair game and sometimes we wont be heard or recognized despite our efforts. Don't give up, keep getting better.