Create your document at the size you intend it to be printed, this can be either a standardised (i.e. A4, A3) or custom size.
If you need the work to flow to the edge, then when you create your new page look for an option to add bleed (3mm is a general standard). 'Hanging' the image 3mm off the edge allows for cutting precision, it makes it easier to cut without the risking a white ‘border’ line. If sending to a professional printer they will, for instance, print an A3 image with 3mm bleed on an A3 plus sheet of paper and then trim down to the correct size.
Select the correct colour mode; RGB (red, green, blue) is for web/video/computer display, whereas CMYK (cyan, magenta, yellow, black) is print.
After opening the document it is good practice to save it straight away, and then routinely saving whilst you are working. Note: saving your file in certain formats will effect how editable it is when you reopen it (i.e. text may not be changed, layers may be flattened).
As a general rule the bigger the dimensions of the artwork, the larger the file size. However it is resolution, the amount of dots per inch (dpi), which plays a key part.
72dpi is generally saved for all on-screen work, whereas your will need a higher quality dpi for print.
For example, if you get an 80kb – 72dpi image off Google and put it on the front cover of you A4 document, it will be very poor quality when printed....
300dpi is often used for print, however for large scale images (where 300dpi would otherwise create too large a file size), 200dpi would be fine. Note: there are some traditional printing methods that require lower DPIs, however it still best to have a high quality 'working file' and save a separate lower quality 'print' version to go to the printers.
Remember: smaller working files are also quicker for your computer to process, especially when you are using effects!
Images from other files can be brought into your artwork by simply cut and pasting. However, files can be also placed in the artwork by going to File / Place / Select desired file, here you can choose whether you want to Link the file. If you uncheck this box then the file will be Embedded.
Linking files means that the imported artwork is connected, but still independent of the document and can therefore be edited separately, and then updated in the document. Linking files keeps the document size lower, however in order to share it with others you will need to supply all linked files or embed before sending (this option is in the links panel).
Embedding files places it in full resolution in the document, unconnected to the original file. It results in a larger document size, however you don’t have to worry about links when you go to print.
There are a number of ways to decrease file size when you have finished the artwork.
Deleting unwanted layers, hidden objects and unused items outside of the artboard. In Illustrator Object / Path / Clean Up is handy for getting rid of empty paths and text boxes.
Deleting unused patterns, symbols and colour swatches. In Illustrator make sure the Colors/Swatches/Symbols pane is visible, and in the top right hand corner of this panel click the small downward triangle icon and click Select All Unused, then pull selected items in to the trash icon to delete. Do this for each of Colors, Swatches and Symbols.
Firstly, make sure you know the format and dimensions required by the person/company you are sending the artwork to. This should be on their company website, but if you’re in doubt ask them, as it will save time and confusion.
Be aware that if sending artwork by email, the limit is generally 10MB, which is not large. Usually for this PDF/X is okay, you can select this under File / Save As / Under Format select Adobe PDF / Under Adobe PDF Preset (where it says Illustrator Default) select PDF/X-4: 2008.
You may want to uncheck preserve illustrator editing capabilities when saving, as this will also lower the file size, but if you do this save it as a copy, so that you still have the editable original.
Other smaller file options under Adobe PDF Preset are Press Quality and Smallest File Size, but with these there can be some loss of quality and editability.
Be wary of compressing files in order to decrease file size as this often lowers the dpi.
If this still results in a large file size, too big to send by email, then file sharing website like WeTransfer, YouSendIt and Dropbox may be useful. WeTransfer is especially handy, as you can send files up to 2GB at a time for free, and you and the recipient do not need an account, whereas with many others like Dropbox, you do. With WeTransfer you also get a notification when the recipient has downloaded your file, it is like a 'digital receipt'.
Okay, you’ve found the exact, and rather obscure font to use within your artwork. This is great - however unless the person you are sending you has it too, this text is going to be substituted....
You will need to make sure that you either email the font file (otf, ttf, etc….) with your artwork, or you can convert the text to an image.
To do this in Illustrator:
In the Menu Bar go to Type > Create Outlines
To do this in Photoshop:
In the Menu Bar go to Type > Covert To Shape
You can also do this by save the file as a Jpeg - this flattens the artwork.
Note: both ways render the fonts uneditable, so please make sure you save an editable version first.