This unique technique uses <span> tag to set alignment, with some additional recipe. Here is it:
<span style="display: block; text-align: ... ">
Your text, image, script, etc here. This text etc can be embedded with any alignment, regardless of what the particular 'div' and CSS settings have determined. This advanced span tags owns.
To use it, just put the command everywhere you want, and change the " ... " with left, center, right, or justify. This advanced span tag can be applied to every part of your Blogger powered website / blog: posts, sidebars, template, footer, etc. It can also be used to alter alignments rapidly, even in one part or one <div>.
Try it. Any problems / questions? Feel free to use the comments section.