Universally, ctrl+c to copy and ctrl+v to paste.
There is a caveat: The terminal requires ctrl+shift+c and ctrl+shift+v because the controls ctrl+c /v are already hardcoded for another puprose in Xterm - the basis of all terminal emulators.
As far as Clipboard manager- the posts above have addressed. 
This may be due to scaling, resolution or which theme you are using. Could you clarify the question (Or provide a screenshot) to detail what you mean by "too sharp"?