Scratchpad Notebook: https://colab.research.google.com/notebooks/empty.ipynb
Open Notebooks from GitHub: simply replace github.com with githubtocolab.com. It will redirect you to a Colab notebook.
Timing Execution of Cell: hover over the cell run icon and you will get an estimate of the execution time taken
Run part of a cell: Click Runtime -> Run Selection button or using the keyboard shortcut Ctrl + Shift + Enter
Most commonly used shortcuts:
- Run cell (Ctrl + Enter)
- Run cell and add new cell below (Alt + Enter)
- Run cell and goto the next cell below (Shift + Enter)
- Comment current line (Ctrl + /)
Jupyter Notebook Keyboard Shortcuts: Click Tools -> Keyboard shortcuts or Just add Ctrl + M before whatever keyboard shortcut you were using in Jupyter. For example
- add a cell above (Ctrl + M + A)
- Add a cell below (Ctrl + M + B)
- Change cell to code (Ctrl + M + Y)
- Change cell to markdown (Ctrl + M + M)
Jump to Class definition: press Ctrl and then clicking a class name
Run bash commands:
- Download dataset from the web with !wget <ENTER URL>
- Install libraries with !pip install <LIBRARY>
- Clone a git repository with !git clone <REPOSITORY URL>
- Change directory with !cd

Mount your Google Drive to Colab:

from google.colab import drive
drive.mount('/content/gdrive')

To upload a file (or several) from your computer, run:
```
from google.colab import files
files.upload()
```

To download a file, run:

from google.colab import files
files.download('path/to/your/file')

Run R programs in Google Colab: You can use R programming language in Google Colab by going to https://colab.to/r. It will open a new notebook with R set as the kernel instead of Python.
“Open in Colab” Badge: You can add a ‘Open in Colab’ badge to your README.md or jupyter notebooks using the following markdown code: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/notebooks/basic_features_overview.ipynb)
Run Rust programs in Google Colab: Go to https://colab.to/rust. Then rust the first cell. Reload the page. Skip the first and run other cells, or write your own codes.

References:

Google Colab Tips and Tricks