When making logos, Photoshop is a poor application to use because it will only waste your time and money. A logo created in Photoshop cannot be enlarged or altered in the same way that a logo created in Illustrator can. Vector-based rendering produces the clearest type.
Go to "Select-Inverse" or press "CTRL/CMD + I" to invert the selection. After inverting the selection, paint outside of it with the same technique to erase the rest of the logo while maintaining a straight edge.
In Photoshop, open the image of your logo. Use the slider to select a suitable degree of Gaussian Blur by going to Filter > Blur > Gaussian Blur. Then choose OK. Now select Filter > Sharpen > UnSharp Mask from the menu bar.
We recommend using a canvas size of at least 500px by 500px and changing the measurement to Pixels. Pixels (px) are a standard unit of measurement in the design profession. You can start with a larger or smaller canvas size, but this is a good size to start with.
Because most logos are rectangular, you'll want to choose document dimensions that are wider than they are tall, so start with _1000 pixel width by 600 pixel height t. You don't need to be concerned with the canvas size at this time because you can easily change it later.