When you are performing a cold call there are basic principles which are very effective.
Leave message but no details: If you are going to explain your value proposition on an answering machine then you will not have a chance to respond to an objection when a prospect listens to it. Also, you don't want leave someone with impression that you are trying to sell something. Best strategy is to leave a message asking them to get in contact with you.
1-2-7: Do not call to frequently. Make it seem urgent but after 3 attempts give up and reproach at a much later date. 1-2-7 is an effective rule on which days your attempts should be.
First attempt is on the 1st day.
Second attempt is always on a following day. The point is to demonstrate urgency.
Third attempt is exactly one week, or 7 days from the first attempt. This is to show your politeness. You want to assume that the reason you could not get into a contact with someone is because they were away or just too busy. You are being polite by giving them space.
Soft rejection is when someone tells you it is not a good time or there is no need currently. Be courteous and don't contact again for the next 6 months.
Hard rejection is when someone outright tells you they are not interested. Contacting them too often will only worsen your relationship. If you got hard rejected, do not contact at least for 12 months.
Smile: One of the most important things to do on a call. When you smile on a call your prospect will hear the difference.
Talk slowly and clearly: Do not try to force as much information as possible into a narrow timeframe that you are spending with a prospect on a call. Too much information in a small timeframe will not be understood, A prospect will get overwhelmed and find any excuse to end the call.
Instead, make sure he/she understands you clearly. By talking slowly you will settle into a pace of calmness, which is a state you want a prospective buyer to be in when you communicate value proposition.
Use casual language: Vast majority of people do not like to be approached formally. During the call speak as if you are talking with a friend, in a relaxed but professional matter. Use first name only, no need for Mr./Miss.
Call handling: Be prepared to:
1. Handle a gate keeper
2. Figure out a decision maker
3. Handle objections
Emails: The same structure as the call. If you didn't get hold of someone over the phone, make sure to follow up with the email right after leaving a phone message. This technique works very well and will increase your response rate.