Don't worry about having a unique concept
I see too many smart people put off of public speaking because of this. It's perfectly reasonable to take an existing concept and layer on your own perspective and experiences. This humanises the topic and makes it interesting. Also, remember that what's obvious to you isn't obvious to everybody. There are always new people joining the industry.
Also don't feel you need to write a new talk each time. Like music or stand up comedy, talks get better with practice. As a side note, I saw the same talk 5 times over the course of 3 years. Each time I took something new away because I was in a different place in my career.
45 minutes is a looooong time to keep somebody's attention
No matter how interesting the subject, a monotone delivery make it hard for your audience to stay engaged. Use your voice (speed, pitch, volume etc) and body (gestures, stage) as a tool to keep things interesting. Try to minimise the "ums" and "ahs". This comes from practice.
Try to avoid the "speaker square dance" when you shift your weight from one foot to the other. It's distracting and makes you look nervous.
(These are all things I still do, to my annoyance).
Try to avoid "listicle talks" if possible. You know the type. Here are 7 or 12 things I think are important, and I'm going to go through them one by one. It's a handy formula, but it make people conscious of time. "Crikey, they're only at number 4".
A few things to avoid
Try to avoid giving a big bio at the start of a talk. I know it's a great way of you "justifying to the audience" why you're on stage, but folks generally don't care. Often it's better to start right in the middle of a story, as it makes the audience tune in.
Typical speaker jokes like "I'm the only thing between you and beer" can be risky. Especially if you haven't been listening to the other speakers and they've already said that about lunch or coffee. I also worry about normalising over consumption of alcohol at conferences.
Asking your audience to perform a task can be risky, especially in front of Brits and Northern Europeans, who would rather curl up into a ball and die that risk the social awkwardness of talking to their neighbours. However... Once people get talking, it's actually hard to get them to stop. If you do have an activity planned, make sure you leave enough time for it to be a meaningful connection.
It's super common to make jokes about finishing off your slides last night or not getting to bed late because you were out drinking While it's good to be vulnerable and human, if played wrong, the message this sends is that you don't care about the audience.
If you are going to present a concept or opinion style talk, you'll probably need to give some back story. Try to keep this short as I've seen plenty of talks that are so much back story, they run out of time to cover the more interesting topics.
The best talks have a really clear story arc
Things that make sense when you read them in your head, often don't gel when read aloud. So make sure you practice your talks out loud half a dozen times to make sure it flows. A surprising number of "natural" speakers have a speaking coach.
I think it's usually better to assume a reasonable amount of audience knowledge. For instance, If in doubt assume folks know what a Design System is rather than spend 20 minutes explaining it to folks. Better to spend that time talking about what you do differently.
Nerves are natural
If you're a little shy at conferences, speaking is The Best way to break the ice. Nobody talks to you before the talk. Everybody wants to talk to you afterwards, largely because they have a way in. As such, public speaking is bizarrely good for introverts.
Nerves are natural. Everybody gets them. Some of the best speakers I know are an absolute wreck before going on stage, swearing they'll never speak again. Then they get up on stage, really enjoy the talk and can't wait to do the next one.
You can't really banish nerves, all you can do is manage them. You may think the whole audience can tell that you're nervous. Generally, nobody has a clue. You are your own worse critic. Remember nerves are really just excitement and excitement is a good, performance enhancer.
Be visible, be reliable
Many conference organisers like to have seen people speak in advance, so if possible try to record your talks, even if they're internal presentations or at local networking events.
Organisers appreciated that you're busy, but also appreciate it if you can respond back to them in a timely manner. One of the reasons we see "the same old faces" is because those speakers are reliable.
There are more conferences and events than ever before. As such there's a huge demand for new voices, especially from underrepresented groups. I encourage you to take advantage of this opportunity and put yourselves forward.
I've shared this thread and some follow-up resources on Twitter - please add you own.
One last thing (I promise). Speaking is fun and provides a great sense of accomplishment sharing what you've learnt to help other people.
However, conference speaking isn't necessary to advance your career. Some of the best, most successful people I know don't do talks. Don't feel pressured into speaking.