Davey, you're not looking at all sharp with those shots mate. It's a shame because you're obviously putting in the time and effort. The shots are nice with nice subjects, but it's hard to get past the fact they're unsharp. With the kit you have you shouldnt be having these problems.
What focusing mode do you normally use? If the TC is forcing you to use manual focusing it could just be that. Do you wear specs? Have you adjusted the viewfinder dioptre adjustment to your own eyesight?
Not all lenses are suitable for use with a TC. No matter how good theTC is there's always some loss compared to using the lens without one. Zoom lenses will not respond as well to a TC as fixed ones. Try leaving the TC off for a while and take some shots without it.
It's very natural with a zoom lens to keep going for max magnification( I do it myself) and it isn't always best. Try to think more about capturing the surroundings and your framing - not just the main subject.
I'm sure there's just something very basic holding you back though Davey, if you let us know a little bit more about your kit and the Mode etc you work in, I'm sure we can get you sorted out!
