I have to set my campaign in a perfect way. I have read many articles each gives different ideas some says concentrate on Volume some says concentrate on CPC. Which type i should select keyword phrase or long tail keywords give me a best idea?
Re: Guide me
To start with I would recommend to go with medium search volume keywords in order to have control on your budget and still get good relevant traffic. You can start with Broad Match Modifier keywords as these will help you identify the type of queries users are searching for. Based on the search query report, you can then create targeted ad groups using Exact match keywords. Start with selected, most targeted keywords according to your website/products. You can always expand it later on.
Targeting high Volume keywords will depend on how much you are willing to pay per day. The more budget you have the more high volume keywords you would be able to target. But if those high volume keywords are not performing up to the mark (i.e. within your ROI), you may either want to drop your positions on those or pause those for the time being.
Until and unless you are achieving your ROI/ROAS there is no harm in paying high CPC. The CPC can always be lowered by optimizing the account i.e. improving your Quality Score and Relevancy. You should be able to pay high CPC on those keywords which are converting for you and you can keep your CPC low on less performing keywords.
Generally, long tail keywords are most targeted keywords but do have lower search volume compared to one, two (or three) word keywords. The shorter the keyword length is, the more generic it would be with wider reach and lesser relevancy compared to long tail keywords.
So, at the end you have to decide yourself how you want to go about and the limitations you have.