This post describe the old ways. For an easier way, refer to Blogger Edit Blog posts options
Some bloggers are not satisfied with the simple "comments" at the bottom of a post which you have to click to view or leave a comment. They want to change it to something else like "Leave Your Comment" for example. To see a blog where that has been changed, surf over to Google AdSense Signup Page. Look at the bottom of the only post. The standard "comment" have been changed to "Leave Your Comment".
This is how you do it. Click TEMPLATE tab, then the EDIT HTML sub-tab to get to the template editor. First, backup your template plus the Page Elements. If you don't know how to do it, refer to Backing and changing New Blogger template. Once you have done it, tick the "Expand Widgets Template" and wait for it to fully expand. Then look for this line of code:
To help you find the code, click ctrl+F and type or copy-paste part or all of the code you are trying to find into the "Find" field at the taskbar at the bottom of the page, and click "Next". The code will be located and highlighted.
Another way to do is is to click inside the template editor window, press ctrl+A to highlight all the codes, press ctrl+C or right-click and select "copy" to copy the expanded template into clipboard, open a Notepad file, paste the template into it. Click Edit > Select All in the menu bar at the top to highlight all the template. Click Edit > Find in the menu bar, and copy-paste part or all of the code you want to find. For example, paste <data:top.commentLabelPlural/> into the "Find what" box, and then click "Find Next".
Replace <data:top.commentLabelPlural/> (highlighted in red) with "Leave Your Comment". Click inside the Notepad file and press ctrl+A to highlight all the edited template, click ctrl+C to copy into clipboard (or click EDIT > SELECT ALL in the menu bar followed by EDIT > COPY). Go back to the template editor. The whole of the original template should still be highlighted. Click DELETE key to delete the original template, then press ctrl+A to paste the edited template in the clipboard into the template editor window (or right-click inside the template editor window and select "Paste"). Click PREVIEW at the bottom of the page and if satisfied, click "Save Template".
If you want to check, click VIEW BLOG to confirm that the standard "comments" have been changed to "Leave Your Comment" (or anything else you had chosen).