First, do not send email to people who didn't ask for it. Of course you want everyone to read your emails. You might even think that everyone wants to receive them. They don't. It's called permission based marketing for a reason. If consumers want to hear what you are saying then they will subscribe to your emails and give you permission to send to them. If you send an email to someone, and they didn't' subscribe, you are a spammer.
Second, content is king. Your email needs to be professionally designed, follow brand guidelines and most importantly contain content that is interesting to the subscriber. Whether you are sharing customer testimonials, talking about product features, highlighting a few sales specials or focusing on new products, you have to give your subscriber what they are looking for. Inundate them with junk that they don't want and you will be considered junk mail.
Third, timing is everything. When you send your emails - and how often - go a long way to determining if they are a welcome bit of info or completely annoying. You need to pick a set schedule and stick to it. No matter how great your information might be. Please remember that your consumers have lives that don't revolve around you, your company or your products.
Fourth, analytics rule. Your email program's analytics will give you great insight into how your consumers are interacting with your email. Are they deleting it unread? Do they forward it to their friends? If you are seeing a lot of 'unsubscribe' then you need to change what you are doing.