Try to put information about your self in the email

Try to put your fullname, website, contact information etc in the signature to improve response rate.
some important people want to know about you before responding to your email.
If they found some information about you in the email then they may feel that they are responding to real people rather than fake ones.

Always use simple Words and Slang

Always keep in mind to to use the simple wording and slang in messages or emails. If you use difficult words for the messages, and the recipient does not understand it, he/she is not going to go through the dictionary for understanding the words and to reply you.
Try to use proper slang.
Example:

Full stop:
The person who drives the plane is called Pilot.

Question mark:
When you are coming back from California?

Semicolon:
Joy is a good player; He practises for daily 5 hours.

Comma:
I like reading, listening to music, hanging out with friends etc.

Try to compress the sending file

Whenever you are to send the attached files, first try to compress the files before sneding it.
As everyone has shortage of time, no one likes to wait for a long download as it is a wastage of time as well as money.
Try to create documents via MS Word as these documents uses very little space.
If you send the bigger sized file in the attachment, recipient may not like to store it due to low memory available in computer or mobile phone etc. and it lowers the chances for the reply from the recipient.
If you have the size of file e.g. 20 MB after compressing it, then try to send the file by file sending service like SEND6, Yousendit, Tonsho etc.

Try to have another look before sending the message

Always try to have another look at the message before pressing the send button.
Reread the whole message and reconsider it. By rereading the message again, you can get the more accurate message than the older one by making some changes to it and you can also correct the mistakes that you have done in it.
For example:

Hi Sarah,

Be there at 6:00. i will wait for you at the gore plaza.

After rereading:

Hi Sarah,

Try to be there at gore plaza at 6:00 pm. i will wait for you.

By reading the message again, you can correct the subject or the information of the message to put good impression on the reader and to increase the chances for the reply from the recepient.