First and foremost, that's a lovely Camellia you have there Pati. And I have to tell you, I just love it when people ask the "How should I prune my (plant)...?" question. Because it allows me to come back with a question too ;) my Q is always: why do you want to prune it? What would you like to achieve?
The fact is, that any kind of pruning will deliver all of the above. So before we dive into your camellia, let me give you some general information on pruning camellias.
When to prune camellias?
Short diagnoses - considering the size and location of your camellia, if I had to choose, I would only prune to reduce the size of its canopy, nothing else.
First - it looks like your camellia it situated in a strategic position next to the house and a path leading somewhere... it is beautifully ornamental and I wouldn't change that.
Second - Reducing its size will remind you what it looked like a few years ago, and give you a clearer view of the house and walking path - it would be refreshing
Third, and most rewarding - pruning will enable new growth, new bloom and a new look. If you excuse my drawing skills, and use the marked up image as a guide you will get all three goals. And as I always say, don't try trimming exactly as I marked (follow the green line. The red lines are to be pruned off). it's just a general guideline. A few inches more or less won't make a difference.
Note: You font have to remove everything I marked, you can just reduce the height on top. As I mentioned earlier, that is what I would do. And you can play with it as you prune, just step back in-between pruning stages, have a good look and decide whether you want to keep cutting, or if you're happy with the result so far. If you are, stop.
Because your camellia is mature, strong and healthy, you can have fun playing with its design. Here's one idea:
If you prune and remove the lower branches (just under the marked orange line), you'll get a tree-like shape. Just be sure to prune those lower branches as close as you can to the main trunk.
Finally, stand back and examine your work - you will have achieved all of your pruning camellia goals in one new style!
Two more tips
One last thing
If you have found my page on pruning camellias helpful, I would love to see a picture of your camellias new look - we can add it to the page and show others what can be done.
I hope that was helpful.
Providing general guidelines on 'how to prune' any kind of plant is important, but there are plants, and there is YOUR plant. So despite there being loads of information on this site, I also provide specific and personalized support. If something wasn't clear, or you're not sure of your plant's name, simply send me a picture with your question. Use the form below and I'll get back to you. In the mean time, see what others are asking.