The most effective email marketing strategies are:
Send a personalized email
Always send a personalized email, so the user feels personal touch rather than a sales email.
Keep your subject line short
Keep your subject line short and attractive. Make sure you don't use any sales subject or bluff statistic, which reduces your open rate.
Segment your subscriber
When you are planning for your email marketing, make sure you have a clear idea about your targeted audience according to age, region, gender, company, industry, a past purchase, etc.
Schedule your email according to the time zone
Maybe your targeted audience is from a different region. Schedule your email according to the perfect time so your email gets land and must be open to your targeted audience.
Send mobile-friendly email
Most people are accessing their emails through mobile, so if you are planning to send an image or infographic, make sure that it will be mobile-friendly and conveyed the way you want.
I hope this will work for you.