Use split to move blocks of text around rather than having multiple terminals open. Open the file you want using the split command:

split: path/to/file

C-w and then k or j will move you between vertically between the buffers when you are not in insert mode (up and down, respectively). For example, this makes moving text between files much easier.

Use the commands enlarge-window-horizontally and shrink-window-horizontally to change the size of an emacs window.