Good advice on LR data management is readily available (Scott Kelby, adobe tutorials, etc) as well as the brief outline above.
One word of caution - pick a strategy and stay with it.
For example, you COULD use a separate catalog for every shoot, and keep each shoot / catalog / files together on an inexpensive and separate HDD.
Or you could use only 1 catalog and organize each shoot into collections as noted above. Eventually your catalog will become large and require more computing power, but this allows searching to be limited to only 1 catalog.
The real question is how long do you want / need to keep your archives. Getting rid of the non-keepers is the easy part, but staying organized is better done in 'real-time'.
Learn to consistently use keywords or a rating system as you go through your shots! This will make it easier to later find YOUR favorites (to post here, enter contests, compare techniques, settings, etc).
As to RAW file management, it is critical to use LR file management and not move the files outside of LR or else you will have hard time using LR fully to its' capability. Once you post-process the RAW, EXPORT the JPG to use as both a backup and for commercial / personal use. The RAW will always remain within the LR catalog you are working in.
If completely satisfied, after exporting the JPG, you COULD delete the RAW files to clear space, but then you lose the ability to make future changes. It all depends on how much you anticipate returning to the project files.
Another time-saver - during import, apply basic camera/LR presets and render 1:1 preivews - and go to sleep/eat, etc. Come back and then pick/choose/rate as noted above. You won't have to wait to see each picture. Takes more time initially, but helps speed up the rating process. Also, if you can, learn to use 2 monitors during your selection/rating. On the second monitor, use GRID view and you can see what shots are coming next, use your eyes to move back and forth and you are not stuck trying to pick out keepers based on the thumbnails.