There are many theories about what makes a photographer a professional. For some it simply means that they get to pay their bills and live day to day from the money made from photography jobs. For others it means that you’ve got a “proper” camera (namely a DSLR) as opposed to a point and shoot or a camera phone.
Knowing all there is to know about photography would, I imagine, have its uses although I am not trying to kid anyone into thinking that I know it all! But if that knowledge isn’t practical then, when you’re faced with an opportunity and things don’t quite go according to plan, it’s really not going to help you all that much.
In my opinion, being a professional photographer means being able to adapt to any given scenario that may arise whilst you shoot, whilst you’re working, If you’re shooting a wedding then this could mean choosing the lens that gets you close enough to the bride and groom kissing while the powers that be won’t permit you from moving from the rear of the venue. Or knowing how to balance the suddenly limited ambient light on the dance floor with whatever extra light you happen to have brought with you. Even a somewhat controlled scenario of a studio portrait session could prove challenging. If your subject arrives with no suitable outfits, do you turn them away? If they detest the way they always look fat in photos, are you going to be able to shoot them in a flattering light?
That’s why the top piece of advice that anyone can give is to shoot. Practice your craft. Every day. Pick up that camera and take a photo. But learn from your photos. Why did it end up darker than you intended? Why is it blurred? Why are the tones just flat and lacking life?
Get others to look at your photos. What do they think of them? An honest appraisal is going to be more valuable than someone saying “that’s nice dear” however.
It is said that, to be truly good at something, a person needs to invest 10,000 hours. Learning and doing along the way. For some people that means picking up the camera at least once a day. 365 days a year. Even if it’s simply for one shot. Wherever you are on your journey of development, get out there and shoot!