What camera did you take the photos with? And how big, and what resolution, does your monitor have? If you worked on/viewed an image significantly smaller than the print size, you may just not have seen defects in the original photo that became obvious when it was enlarged. Lesson Number One of digital photography is that higher (digital) resolution doesn't automatically give you good/pictures just because "moar pixels", and viewing a high-res image at a small(er) size will mask defects that become obvious when viewed/printed at a resolution that more or less "just fills out" the image space.
As for future workflow for print work, I think your first step needs to be "calibrating" your familiarity/expectations/technique to the sort of image quality your camera can produce at the resolution/image size of the photos you want to end up with. If, for example, you're using a phone camera, you're going to have be a lot more careful about taking the original photos if you want good looking 11x14 prints than you have to be to get good looking social-media-size "snapshots". Assuming the camera is capable to taking photos of the quality you want in the first place, of course...
As for the monitor's calibration, that wouldn't (or shouldn't) have anything to do with blurriness or pixelation, rather than the image color and characteristics like contrast and "brightness" that ultimately depend on color reproduction when printing photos. But when printing photos, you also need to know what color space the printer/lab uses and how that relates to your monitor's specs and accuracy. And for "really good" prints, you're probably better off using a pro/prosumer lab, too.