In the Show conversations option on each page you can choose to display up to 100 conversations.
Every time you handle a conversation like archive, delete . Gmail will bring you back to the main interface by default. So storing or deleting each conversation . is very time consuming.
However, you can set Gmail to automatically forward to the previous conversation or the next conversation by selecting the appropriate Radio Button located next to Auto-advance in the general settings section.
Also on Gmail, there are many other hidden features that even longtime Gmail users won't discover.
Good luck!