The key to a great paella is the rice. I think a lot of people make the mistake of loading up the Paella with too much rice and meat, seafoods, eggs, peas, etc...for me, how the rice tastes is the most important aspect of a Paella(no offense meant this is just mr personal opinion)
Never ever overload your paella. Just put enough rice to go half way of the pan (rivets) once cooked. That will ensure all the flavor of the broth stays in the rice, and not evaporate into thin air. Remember all the broth has to be soaked by the rice and not by air.
Make sure your broth is flavorful. Just add a few ingredients to complement the rice. Wether it's all meat, seafood or vegetables. Remember the key is the rice. All the rest is secondary. It's nice to have the 'socarrat' which is the Burt bottom part known as 'tutong', but again please don't overdo it. No one likes eating burnt rice. A little crust or browning will do.
Speaking about rice, the best rice to use (for me) is arroz Bomba de Calasparra. This is short grain rice, which absorbs all the flavor of the broth. Be careful though, when using this, I add an extra cup of broth per cup of rice(from the usual recipes) since it absorbs much more than the usual Japanese or Calrose rice use locally to Make Paella.
If you want to eat this the traditional way like In Spain, once cooked, put the pan in the middle of the table, give everyone a wooden spoon and eat directly from the pan. Just make your own imaginary divisions (think pizza slices but made if rice) and no crossing of the imaginary lines.
My 2 favorites are the all meat paella (shown on top) and a Paella de Bogavante (Lobster Paella)