One tip I didn't see mentioned (though it's pretty common in tmux) is to use the default window layouts for organizing multiple panes. You do this with Ctrl + b followed by esc + <num>.
esc + 1: All windows take up equal space horizontally, and stretch the full vertical width
esc + 2: All windows take up equal space vertically, and stretch the full vertical width
esc + 3: The first window takes up half of the screen vertically, and all remaining windows divide up the space equally
esc + 4: The first window takes up half of the screen horizontally, and all remaining windows divide up the space equally
esc + 5: Windows are divided into two equal columns horizontally, and split remaining space vertically.
Even if I have to alter the sizes a bit usually, the pre-defined layouts are super useful for positioning different windows.
esc + 1: All windows take up equal space horizontally, and stretch the full vertical width
esc + 2: All windows take up equal space vertically, and stretch the full vertical width
esc + 3: The first window takes up half of the screen vertically, and all remaining windows divide up the space equally
esc + 4: The first window takes up half of the screen horizontally, and all remaining windows divide up the space equally
esc + 5: Windows are divided into two equal columns horizontally, and split remaining space vertically.
Even if I have to alter the sizes a bit usually, the pre-defined layouts are super useful for positioning different windows.