I'll suggest you to some tips to choose your template for blog

1. Choose a template that suits purpose of your blog:- look and feel of template reflects a big impact on the reader. So you must be very choosy.Template is just like your first impression on reader.So Choose a template that glue your reader for long time.

2. Start with two column theme:- If you are begginner in blogging then you must choose a two column template as compare to three column template.

3. How to use image:- Choose the type of image and banner that fits best on template. Pictorial representation puts more visualization effect on your reader than textual impact.

4. Choose simplicity over complexity:-Choose a best possible simple template that make your blog easy to read.

5. Change if it's not working:- Change a template that will not work because there is no point to glue with a formula that is not working for long time.
By experimenting you know the several new doors of opportunity. So never hesitate to experiment on strategy that is not working.
Don't change your fully customize template just change a bit rather entirely and then guage
it's effect.