I can't find anything, anywhere in adobe that says dpi, I finally figured out how to adjust the pixels but it will not let me go any higher than 100 pixels and the image looks awful! It's choppy and just plain bad... I've never had this happen before but nothing I do, resizing the canvas or the image fixes it.
I'm trying to do a text image for a t-shirt so 10inX10in, some use of Clipart is involved... and the image is tiny even though the canvas is set to 10 in.
I can't figure this out and am about to scrap the design altogether.

Start with this
http://www.tutortanith.com/createPSimage.htm
I suspect you will be better served by using the tutorials that have video
http://www.tutortanith.com/resources2.htm#photoshop
To get larger text type the numbers into the box that has the drop down - start with 300