Increase or reduction margins in the Page Setup form to fine-tune the vertical and/or horizontal print area available.
Landscape orientation usually yields the best results (especially on single-page output), but it is sometimes useful to see if portrait is better.
Font sizes will be rescaled by whatever has been entered or calculated in the 'Scale %' field, so font size requests will seem to be ignored if you are using the 'Force to One Page' or 'Pages Across/Down' feature (in File, Print). If you are not using the 'Force to One Page' or 'Pages Across/Down' feature (in File, Print), consider increasing the font size (via Format, Fonts and Colors) of one of the tasks (for example a blank line dummy task) to cause all the task lines to increase the vertical space they use... but note that this will also increase the horizontal space each column requires.
Sometimes the program will still want to print just a little bit more date range than is specified by the Date Range entries in the Print form. Ways around this include: entering a smaller date range; showing higher precision in the date scale (for example, display the date scale in months instead of quarters).
As a last resort, if "Print Legend on Every Page" enabled in the Page Setup form, you can get TLW to scale the excess part of the output onto other, discardable pages. In other words, bump up the "Scale %" value in the Print form to force TLW to want to print out to more pages, and check the Preview to see if the portion of the printout you want comes out the way you want. Set the 'Pages' portion of the Print form to print only 1 page if you want to test just one page of output.