Make it a practice to purge all unused style definitions. Each time a material or color change occurs, the file caches the style definition.
Parts
Suppress large feature patterns on parts. Consider using a bitmap texture in place of large feature patterns.
Reduce unnecessary details in parts. For example, do not model physical threads, fillets, and gear teeth if the detail is not required for manufacturing.
Minimize the usage of Move Bodies in a multi-body part. Use click to add to group moves into one feature whenever possible.
Drawings
Keep the size of drawing files as small as possible by minimizing the numbers of views on a sheet.
Minimize the number of sheets in a drawing file.
Before inserting a .bmp into a title block, make sure the .bmp is saved in the smallest file size permitted by your company's standards. In Microsoft Paint, the default file type is 24 bit-Bitmap. Reducing the file type to 16 Color or Monochrome type Bitmap, will increase capacity.
In the Drawing tab in Document Settings, set Always in Bitmap Resolution drop-down menu with a low bitmap resolution to help reduce memory consumption when working with large or complex models of shaded views.