Hope you're doing great! As you know email design is extremely important - it can boost your click-throughs or make people trash your emails. I won't tell you which colors to use or which fonts are the best, but I'm here to show you most fatal mistakes of email design, so you can fix yours. Please enjoy!
1. Forgetting to say Hi!
Your "Hi!" is your header - your header must be informative and recognizable. It's the first thing recipients see - make it look perfect. What about ordinary "Hi!": Show respect to your subscribers - always salute your subscribers, wish them a good day and just stay polite.
2. Something wrong with the fonts.
Words is what you reach your audience with, so you should make them look good and readable. If you use fonts that are too small then you make it hard to read for seniors. Also, emails are viewed on smart-phones, so increasing fonts is a good idea.
And if you use too many fonts then your email look like a task on a MS Word exam in a 5th grade - too messy.
3. Color mistakes.
Don't use colors too bright or fluorescent - they will steal all the attention from your call-2-action and probably leave a bad impression.
Don't use too many colors - the best option is to choose 2 main colors and play with them. Other colors should be toned down.
Light text on a dark background looks creepy, non-corporate, etc. Better use dark text on a light background. Stay mainstream here :)
4. Pile of Information.
Few problems may appear here. First one is forgetting about the table of content or information hierarchy and the second one is putting all the text in one piece. Always split your texts by ideas and short topics. Each little piece of your text should provide info on a small topic, feature, idea. It's much better to have 5-pieces of texts than to have it all in one piece.
5. Bad images.
If you're using default clip-art or images that are used by every 2nd marketer then you're still amateur. Images are attention catchers - make sure they are great.
6. Not using a corporate style.
Your corporate style (colors, templates, image types) is your "face". Stick to one corporate style. Just imagine you're changing your haircut once in a week, changing apparel style and then wondering why people you know don't recognize you on the street.