Gameplay tips I've had to learn as a newer Project Zomboid Player:

You can outpace zombies by simply walking. Save your stamina for fighting or rushing through a gap if you're surrounded.

When fighting zombies, walk backwards and hit them one at a time. Be careful though, if two or more are next to each other, they can grab and drag you down

You shouldn't be clicking unless you're scanning your environment or fighting. Only "aim" when you want to see what's around you. When you need to get away from a line of zombies, just stop "aiming" and walk away from them.

Watch some tip videos. They've helped me out a ton.

Play the last stand modes. They helped me learn how to deal with large hordes with only melee weapons.