docs: add virtual environment and pipx installation notes

- Add recommendation to install within virtual environment
- Include pipx installation option for global use
- Improve installation section organization

README.md

@@ -20,7 +20,13 @@ Compatible with Python 3.11, 3.12, and 3.13.
 
 ## Installation
 
+It's recommended to install pip-add within a virtual environment to avoid conflicts with system packages:
+
 ```bash
+# Create and activate virtual environment
+python -m venv venv
+source venv/bin/activate  # or `venv\Scripts\activate` on Windows
+
 # Install from PyPI
 pip install pip-add
 
@@ -28,6 +34,13 @@ pip install pip-add
 pip install --upgrade pip-add
 ```
 
+For global installation (use with caution), you can install with pipx:
+
+```bash
+# Install globally using pipx
+pipx install pip-add
+```
+
 ## Usage
 
 ### Installation