Begin by running the desired query in Looker that retrieves the data you want to move. Use Looker's built-in export functionality to download the data as a CSV file. This can be done by clicking on the "Download" button after running the query and selecting the CSV format. Save this file to a known directory on your local machine.

If you haven't already, download and set up DuckDB on your local machine. You can download the DuckDB binaries from the official [DuckDB website](https://duckdb.org/). Follow the installation instructions for your operating system. Once installed, you can interact with DuckDB through its command-line interface or a Python script.

Open your terminal or command prompt and navigate to the directory where you want to store your DuckDB database file. Use the DuckDB CLI to create a new database by executing the following command:
```
duckdb my_database.duckdb
```
This command creates a new file named `my_database.duckdb` in the current directory, which will store your data.

Use DuckDB's `COPY` command to import the CSV file you exported from Looker into a new table in DuckDB. Open DuckDB's command-line interface or use a script and run the following command:
```sql
COPY my_table FROM 'path/to/your/exported_file.csv' (DELIMITER ',', HEADER);
```
Replace `my_table` with your desired table name and update the file path accordingly. This will load the CSV data into DuckDB, creating the table if it doesn't exist.

After loading the data, it's essential to verify that the data was imported correctly. Run a few `SELECT` queries in DuckDB to ensure the data looks as expected. Check for common issues like mismatched data types or missing values. For example:
```sql
SELECT FROM my_table LIMIT 10;
```

To improve performance, consider optimizing your DuckDB table. You can create indexes on columns you frequently query or filter. For example, to create an index on a column named `id`, use:
```sql
CREATE INDEX idx_id ON my_table(id);
```

If you need to regularly update your DuckDB database with data from Looker, consider automating the export and import process using scripts. You can use shell scripts to download the CSV from Looker and load it into DuckDB periodically. Schedule these scripts with cron jobs (on Unix-based systems) or Task Scheduler (on Windows) to automate the process.

By following these steps, you can effectively move data from Looker to DuckDB without relying on third-party connectors or integrations.