The first reply mentions buying a higher fare. I would focus #1 on just finding R availability. If R is available, there is no need to go above W. This means considering different routing and times.

If you are forced to waitlist, ofcourse you can buy the highest fare you can but that isnt always an option. If you are close in, its worth checking the inventory (or even seat maps). If the C looks empty, you should have a better chance than if its completely full.

If you aren't flexible at all, then there is nothing you can do to increase your chances. The only think you can do is monitor R like a hawk and call in if it opens up.