I’ve found many tenants and practices of the Stoics helpful in developing tranquility and happiness in my personal life. The Stoic philosophy is surprisingly relevant in modern society. You don’t have to believe in Greek gods or sleep on the floor to find Stoicism useful.
Basic Ideas in Stoicism
- Only concern yourself with what you can control
- Accept that which you cannot control
- Use reason to tame harmful emotion (fear, grief, pain, greed)
- Avoid the trap of wealth — it will not lead to happiness 
Stoic philosophers came up with various techniques for achieving the above, such as negative visualization and self-inflicted poverty.
Below are some resources for those looking to incorporate Stoic ideas into their personal philosophy, or for those interested in what the Stoics taught.
- Meditations - Aurelius
- Letters From a Stoic - Seneca
- On the Shortness of Life - Seneca
- Enchirideon - Epictetus