Thank you for your comment. There are a couple of things I have done in order to increase the sharpness in my images. In order of priority, after I noticed that my pictures were not as sharp as I liked them to be, I did the following.
1. I calibrated the Diopter on my camera. This is a useful link on how it is done and is the one most important thing to do.
2. I started to use Manual focus rather than automatic. As you know, especially when zooming in on a subject, it is tricky to hit the right spot that you want to be focused on.
3. I reduced Shutter speed and increased ISO so that I would have less camera shake when doing handheld, which is the majority of the time at the moment as I am missing a part form my tripod, the one to actually connect the camera to it... All depend on available light of course.
And of course, there are a lot of images taken where the focus is not right and it is not as sharp as I would like it. One thing I have learned is that it takes about 100 pictures to get one decent photo and a 1000 picture to get a great one. My number of great pictures are very limited hehe.