In rRecent daysly, I have been thinking about how I can improve my English. Recently, I have been thinking about how I can improve my English.

In recent daysは正しいことは正しいですが、recentlyの方がよく使われる気がします。

UOf course, utilizing this site, of course, will help me improve my English, because there are so many kind English native speakers here. Of course, utilizing this site will help me improve my English, because there are so many kind English native speakers here.

Yet, sometimes, I feel it would be a good idea to work overseas. Yet, sometimes I feel it would be a good idea to work overseas.

That comma there was unnecessary..but it isn't incorrect though. It's just me being picky here since your English is perfect. Just look out for punctuation. :)

Yet, sometimes, I feel like it would be a good idea to work overseas. Yet, sometimes, I feel like it would be a good idea to work overseas.

I don't know whether there are job openings in the states, Canada, the UK, and other English speaking coutintries for those whose native language areis Japanese. I don't know whether there are job openings in the states, Canada, UK, and other English speaking countries for those whose native language is Japanese.

I don't know whether there are job openings in the sStates, Canada, the UK, andor other English speaking coutintries for those whose native language areis Japanese. I don't know whether there are job openings in the States, Canada, the UK, or other English speaking countries for those whose native language is Japanese.

I can't explain it but having "and" there feels unusual to me. Maybe someone more proficient could explain it.

I don't know whether there are job opening in the sStates, Canada, the UK, [and/or] other English speaking [coutintries] for those[people] whose native language are[is] Japanese. I don't know whether there are job opening in the States, Canada, the UK, [and/or] other English speaking [countries] for [people] whose native language [is] Japanese.

I don't know whether there are job openings in the sStates, Canada, the UK, and other English speaking coutintries for those whose native language are Japanese. I don't know whether there are jobs in the States, Canada, the UK, and other English speaking countries for those whose native language are Japanese.