This tutorial will show you how to create an effective, glassy button in minutes using Illustrator, like that shown below.
Open Illustrator, create a new document and select the Rounded Rectangle Tool. Draw a nice button shape onto the canvas, while dragging the object to create, press the up and down arrows to adjust the curvature. Now give the stroke colour no colour and add a nice gradient as the fill colour, make the gradient vertical with the darker of the colours at the bottom. In this instance I have used the colour #c3262e at the top and #8c181b at the bottom.
Once that is done, copy and paste the object (CTRL + C, then CTRL + F) then shrink the image so that there is an even gap between the two, this usually means shrinking the vertical slightly more. With the new object selected replace the top gradient colour with white (#ffffff) and reduce the Transparency to around 25%. Your main button is now created.
Now select the text tool and type the button text in white, with a nice, strong font, in this case it is Helvetica LT Compressed. You can then add a shadow to the text to help it stand out. Go to Filter > Stylize > Drop Shadow and you want a very subtle, not too distant shadow. These proportions may change depending on the size of your button but I used: Opacity 50%, X and Y Offset 0.5mm and Blur of 0.3mm.