One of the first things you need is a good headshot. Can you do them yourself? Yes and know... selfies don't always make a good headshot. The caliber of the camera and the size of the image can be an issue. Here is an example of what I mean.
I have my head in the shot... but, look at all of the other items around me... like the other 2 cameras behind me... not to mention the other people! The focal point should be you as the actor. Here is an example of my main commercial headshot:
Notice my head is in focus while everything else around me is slightly out of focus! Now here is my Theatrical headshot:
Once again my face is the focus not the surrounding area. Also notice that the look is different. This allows me to show a different look or feel. Sometimes they want a diversity in your character... this shows just that!
Now have I used lower quality pictures... yes I have... for example I was in the need of a particular look. The only option I had was a lower quality picture. Here is an example of one I submitted just a few days ago.
Now this is a full body shot where I am dressed in a more urban cowboy look. It works in a pinch. What I suggest is when you locate a photographer that specializes in Actor photographs, see how many changes you can do. This will allow you to have different looks. Here is another example from the shoot where my headshot is from:
This is a Mid Body shot with a totally different look... this was a change that allowed me to show the mob look or cop look. All of these shots are asked for from time to time. The 2 main shots requested are headshot (first) and full body shot. So why do they need these different shots? The casting directors job is to select the people that look this role. If you are not receiving casting request as an extra it could be several things. One of those is your look. Showing diversity is a plus. Now if you are looking for speaking parts... you have to look the part first. Then you will receive either an audition time or asked to shoot an audition video.
Now you need to ask yourself... am I receiving the result I am looking for with my current headshots? If you are not then seek a professional photographer that can take your pictures. Then you can take your self to the next level!