The biggest mistake made in these is the use of Arial. It's trash; a ripoff of Helvetica. Much like New York which is a ripoff of Times New Roman. Nearly all
typographers will agree.
If you show a professional these, you won't get too far. Arial & Comic Sans MS are the worst fonts you could possibly use. They are widely available because of MS putting them in Windows. Consider using
quality commercial fonts. I have a little over 3,000 typefaces.
A few of these logos look... very amateurish.
Avoid the corporate "Swoosh". It's cliche and overused. Like "When in doubt, use the swoosh". Wrong. Example: Capital One Bank and many more.
It has to be timeless. Is your logo going to last for 5,10, 20, 30 years? Example: Coca-Cola (Pepsi had other plans. They try to stay "Fresh".)
Make your it memorable. You want it to stand out and be proud of it. You want people to look at it and be able to ID the company within 30 seconds. Example: NBC (It stands out and anyone would know it)
It has to be simple. An overdone logo will do more damage in the long run. Less is more in this case. Example: Apple (Apple is king of simplicity)
Versatility. Vectors are the way to go. They can be made in Adobe Photoshop or Adobe Illustrator. A vector allows you to scale the logo as big as billboard or small enough for a business card without losing any quality.
Color choices. Stick to one. The less, the better.
Typefaces. Needs to be limited to 2 or less. Most pro's will choose 1 typeface and go with that. They must be licensed for commercial use.
NEVER BORROW! Yes inspiration is good, but don't use another companies small detail in your logo. Yours needs to be 100% original.
Stay away from trends. You'll be outdated quicker than you can blink. Trends and 'fads' come and go, that means your logo will too. It will interfere with making it memorable and timeless.
My personal logo took nearly a year to come up with. It combines both the "C" and "D" in lowercase form. The typeface I chose is
Gotham -
Bold.
You should consider joining
deviantART. Best place to get feedback on topics like this from Pro's and Amateurs alike.
I've had my fair share of positive and negative feedback. I take it all as someone helping me get better at something I have a passion for.
Oh I agree, encouragement is a good thing. But bringing in accounts isn't worth anything when they drop the company because of uninspired, lackluster designs. Going ga-ga over mediocre designs that look like they were created by an 8 year old in MS Paint is a whole other ballgame. No one ever improves if they're always told their stuff is amazing.
I 100% agree with this.