There's probably going to be some back and forth until you feel comfortable with what's going on. Views help you decide how to tag, and tags help you define your views.
Best bet would be to avoid thrashing. MC has many tools that can help you maintain and organize, and often new users work against the tools rather than let the tools make things easier.
Another best bet would be to not try to organize everything at once. Pick an album or two, and work with those to get the hang of things. Select all the tracks for 1 album, and set the Album tag. If there is one Artist, set the Artist tag. Then Genre. The default views will generally work well with just this. You can organize and refine from there. And there are lots of shortcuts to making this all really fast and easy.
The default views are nice, but I feel they often trip new users because the meta data for their files is not consistent, so they work hard to try to force the matter (a common issue - why are my albums split into many "folders"?).
You can probably intuit by now that some of us enjoy Panes views. When tagging and organizing, panes views are typically the best choice. Since you're just starting, create a new blank Panes view, adding Album, Artist, Genre, etc. From here, continue to customize so you can learn how MC groups, sorts, and allows you to filter and select your tracks.
Here's a good view helper to at least give you some ideas of what's possible:
Views:
http://yabb.jriver.com/interact/index.php?topic=68960.0