One thing missing from @petschge's reply: adding more telescopes! This will not improve the imaging the smallest possible features, but will make features larger (disk and / or jet components) more prominent. The more telescope pairs with different distance between them are added, the more complete the picture will get - up to a limit of having a single antenna roughly the size of Earth.

Furthermore, adding more telescopes will help better image the fainter features in the image (due to larger total collecting surface).