Always run into one problem or the other after uploading to liveserver

I generally follow this wp-beginner guide when I need to move a site from localhost to a live server. Once or twice it has worked okay with only a few broken links or other minor problem to resolve. Most times however, I always experience some initial difficulty with the live site. It may be too slow, some pages may not open altogether, some assets or code that were included in the development stages may not appear, etc. I want to know why this happens and how to avoid it in future.

Thanks.