I currently use a 2015 Macbook Pro 13" with 8GB of RAM and 2.7Ghz i5 processor.
As my previous machine was a pretty weak one, I got used to reducing the amount of running applications & browser tabs. If I don't use something, it's not open or it's turned off (Bluetooth / Wi-Fi). I don't have unused applications installed neither (except those that were installed by a more complicated build process).
What's almost always open is a terminal window, maximized to the size of the desktop and running various applications using multiple tabs. I prefer Hyper's built-in tabs over
tmux, because it's faster to open and to close them, and it doesn't block key events. Spotify is also open most of the time.
If I work on a project with a more complicated file structure (I try to avoid these in my personal projects), I use Atom as an editor, in full-screen mode, and the terminal's width is reduced to the half of the desktop.
Front-end projects are previewed with Beaker or bundled + served by
budo and viewed in some other browser.