What? CMYK? RGB?
CMYK (Cyan, Magenta, Yellow and Black) are the colours used in the printing process, whereas RGB (Red, Green and Blue) are the colours used by screen displays such as your monitor. Every printing dot in CMYK is produced by adding any amount of 0 to 100 of each Cyan, Magenta, Yellow and Black to each other. On the other hand any screen dot by RGB is created by putting any amount of 0 to 255 of each Red, Green and Blue beside each other. Therefore the value of white in CMYK is 0,0,0,0 while in RGB it is 255,255,255. If your design is set to be published by any printing machine then it should be in CMYK format and if the same design is going on display by any Monitor or TV it is expected to be in RGB. Colours are slightly different in RGB and CMYK, mostly, bright RGB colours produced by your monitor cannot be reproduced in print using CMYK. If you want to have one specific colour to be printed in CMYK as exactly as viewed in RGB, then designers usually suggest Pantheon Colors in which that specific colour will be printed separately as extra on the printing material.
Why my print is not as sharp as Monitor?
Most of the designers do their artworks in RGB and at the final stage they just convert it to CMYK and send it to printer. They mostly do not know how the printer works and how they should enhance their colours. Right after converting the artwork to CMYK the designer should reduce and/or balance any components of C-M-Y-K while keeping the colour as close as the original design in order to get a better quality in print because printing process involves many machines that do physical alignments which could not be 100% accurate. This offset will make a print a little (or much) blurrier than Monitor. Ask your designer to retouch your artwork and eliminate/balance components to make it sharp! (Once the enhancement is done, designers usually convert back the CMYK artwork to RGB to have a more compatible RGB and CMYK of one artwork.)
Why my design has Bleed, Trim, safe, grip (leap) area? What are those?
The very edges of the document are called the bleed area. To prevent an unwanted white border (in printing) or missing border (on Monitor) at the edge of your document, be sure to extend your design all the way to the edges according to your media. Trim edges which are inward to bleed are defining the final actual viewable of artwork (the area between bleed and trim in printing process will be cut out, and on Monitor it will be hidden under mask or edges of screen). Safe area is also even more inward to trim and is considered as cancelling the probability of any regular offset that might occur in printing or in displaying. Grip area is only in printing process in which one side of your document should be even extended more outward than bleed in order to let gripper machine take the printing material (such as paper) to move or fold it.
(to be added & updated)