Just like a direct sales letter, the subject line of your email is usually the most important part of getting your readers to actually read your email. If you have a compelling subject line the chance of your email improves dramatically.

According to a recent MarketingSherpa.com survey, 40% of email marketers said testing changes to just their subject line had a high impact on their return on investment (ROI). 45% said subject line changes accounted for a medium ROI and only 15% said that testing changes to their subject line results in a low ROI.

For every email you send you've got room for about 50 characters in your subject line so use them wisely to improve your open rates. Below are some tips to help improve your subject lines:

1. Test the subject line – Take a look at email campaigns you've sent in the past. Which subject lines worked the best and gave you the highest open and conversion rates? You might find that for a particular topic there's a general trend or subject style that resulted in higher open rates.
   
2. The subject of importance – Try and put as much important and relevant information into your subject lines as possible. For example, if you're sending out an email about a special offer make sure the product name and details on the offer appear in the subject line in a clear and concise format such as "$40 off ACME Widget Until - Today Only".
   
3. Personalize the subject line – If you have details about your contacts then you can use them in your subject line to get their attention. A subject line containing the contacts first name can sometimes out-pull one that doesn't.
   
4. Avoid spam keywords – Most email servers automatically filter out any emails that contain spam keywords in their subject line – Words such as free, stock, ebay, password, mortgage, etc all trigger spam detection software so keep them out of your subject lines at all times.
   
5. Trigger curiosity – The best way to improve your open rates is to pique the interest of your contacts. A compelling headline that entices them to open and read the contents of your email can do wonders for your conversion rate. Headlines that trigger curiosity can sometimes work well for example: "Hi [First Name] - I have a question for you.".
   
6. Make the offer clear – If you're making a special offer to your contact then be upfront and include it as part of your subject line. People love bargains and special offers so let them know about it before anything else.
   
7. Emphasize the benefits – We use this technique for our newsletters. We always use the format of "Newsletter – [Benefit]". In our case, benefit is always the title of an article contained in the newsletter, such as "Company Newsletter – 10 Tips for Better Subject Lines". It works every time ;)
   
8. Easy identification – Make sure your contacts know the email is coming from you. Deceptive subject lines can confuse people so always try and including your company name in the subject line. Also, make sure you set the "From" attribute of your email to include your name and your companies name, such as "From: John Smith <john@acme.com>".
   
9. Exclaim nothing – Avoid using excessive punctuation at the end of your subject lines. Google bans punctuation from AdWords ad's for a reason – too much hype can annoy and confuse people.