From doing a design course our lectures always told us an effective logo would be one that is Memorable, and Meaningful, which thinking logically this would be correct because it is easier to recognise a company by their logo.
Preparation & Simplicity
It is important when faced with the task of creating a logo, you are prepared for the task ahead, when creating a logo I would look at my client and see what they represent and how I can make their logo represent their company.
I would then look for inspiration from companies that are in the same industry but Never imitate their logo as this is pointless the reason for a logo is to help make the company recognisable no one wants their company to be confused by another.
Start to sketch its always better when you get a visual representation of what you are trying to betray.
Keeping the logo simple is another important factor on how to make your logo stand out as the simpler it is the quicker someone can match it to that particular company.
It is important for the customer to remember the logo as the logo fits the overall message. If the logo is good at its job it will be help customers recall to to buy of the company meaning repeat sales and it helps them remember you exist which they will be able to recommend to other people and word of mouth helps a company a lot.