I guess one of the most important questions to ask is - do you intend to consume any sort of substances (alcohol, etc)? If you've never been to a festival before, I would first and foremost want to make sure you understand the prevalence of substance consumption and make sure you are safe above all else (stay hydrated, don't overdo it, etc).

As far as your concerns go...
1) You will meet a lot of people at festivals who go alone. It can actually be really fun to attend a festival when there is no one there who knows you to make you feel self conscious; I'm a huge introvert and I find that I can be myself more fully among strangers because I don't really care what they think of me. I would just lean into it. If you're nervous, go ahead and say so. You'll find that a lot of people will go out of their way to help you feel more at ease if they know it's your first time and you're alone.

2) If approaching strangers isn't your thing and you don't want to look awkward standing around, bring something to do. You'll see people with hula hoops, juggling, etc - if you have a skill like that, it's a great icebreaker. If not, that's okay too! Find someone who is doing something like that and compliment them - easy icebreaker. A simple idea is to bring bubbles - when you're feeling awkward, just start blowing bubbles and you'll find yourself surrounded by new friends in no time.

3) Unless the person is giving you creepy vibes, just embrace it. If you are constantly trying to pretend you aren't alone, you'll cause yourself more anxiety than if you just lean into it. If this is an exercise with a goal to empower yourself, just be honest. Say something like "Well I'm actually usually pretty shy but I decided to be brave and put myself out there all by myself today!"

Just remember tons of people at festivals are there for their first time and are nervous. That's okay! Just make sure you're taking care of your body's needs and do your best not to close yourself off from other people and you'll be just fine.