the best way to learn is to try. all these things that only apply to "real" sites can be tested in smaller doses. try setup a "scalable" blog site.
setup an artificial system that can't stretch very far by limiting the memory / instances of your web server e.g. then hit it with more than you know it can handle. deal with that how you think it should be done. if it works for 1000 -> 10000 requests the same might work for 10000 -> 100000 as long as your scale technique doesn't depend on small numbers.
same goes for all the other things you mentioned, they can be tested and coded for without having more than a "blog site" as a test platform. just do it :) code away!
the same applied to a "testing environment" would be to make yourself a 2nd copy of your blog site. push to the copy, make sure things work, then push to the main site. possibly even automate that 2 tier push by writing tests that can be tested without user intervention :)
setup an artificial system that can't stretch very far by limiting the memory / instances of your web server e.g. then hit it with more than you know it can handle. deal with that how you think it should be done. if it works for 1000 -> 10000 requests the same might work for 10000 -> 100000 as long as your scale technique doesn't depend on small numbers.
same goes for all the other things you mentioned, they can be tested and coded for without having more than a "blog site" as a test platform. just do it :) code away!
the same applied to a "testing environment" would be to make yourself a 2nd copy of your blog site. push to the copy, make sure things work, then push to the main site. possibly even automate that 2 tier push by writing tests that can be tested without user intervention :)