I've been working a lot with other designers files lately - either in collaboration or expanding on an existing business and have come across a lot of frustrating moments. Quite simply it seems that there is a lack of knowledge about finishing a project. Fonts aren't collected, color is inconsistent from file to file or there is no clear design aesthetic. If you're in the starting stages of freelancing use these helpful reminders when completing a project:
PROPERLY NAME FILES While your working on variations of each file it's important to find a system that works for you. I end my files with version numbers: _v1, _v2... and never hand off a file until it is complete. When you start to mix version numbers with dates and throw in the word 'final', you, or anyone else, will not know which file is more recent (and you can't always trust the last modified date).
CREATE BRAND GUIDELINES After you've put hours and hours into an identity system make sure it remains consistent! It's as easy as making a single-page brand guideline that includes fonts used and the color palette (in Pantone, CMYK, RGB and Hex). If you want, you could take it a step further and specify how to treat a headline, what photography looks like and how design elements interact with one another. Having this will make you look more professional, you'll be able to maintain control of the design and it really forces you to be aware of the decisions you're making while designing. Check out: I Love New York Brand Guidelines, Pinned Guidelines, Christopher Doyle's Identity Guidelines
HAND OFF FILES You don't need to hand off all your files but handing off logo files is a MUST. Make sure you outline all the fonts and expand shapes. Give your client an .ai, .eps, .pdf and .jpg logo files. If there are any illustrations, patterns or social media icons include those files as well.
The more support you give a client at the end of a project the more likely their brand will remain consistent.