If you are trying to compile a particularly large LaTeX document (or one containing hugely complex Tikz diagrams / charts) you may find you run out of memory. After externalising all the Tikz figures, if you still run into the limit you can increase it! [...]

Attached is my PhD thesis. [...]

To include the watermark on every page:

\usepackage{draftwatermark}

To include the watermark on the first page only:

\usepackage[firstpage]{draftwatermark}

To change the watermark text:

\SetWatermarkText{MyWatermarkText}

To change the darkness/lightness of the watermark (range from 0.0/black to 1.0/white):

\SetWatermarkLightness{0.8}

To change the size of the watermark:

\SetWatermarkScale{4}