Custom Blogger templates are way more complicated and feature rich rather than default templates. People pay money for qualitative product and than... just spoil it. The reasons? Well, it may be absence of basic knowledge or absence of basic aesthetics. May be something else. Or may be it is an intention?
So, what to do if one wants to make the blog based on custom premium template badly-looking? There are many ways and possibilities. First rule: if a custom template has pre-formatted post markup (and it is likely too be) do not use Edit HTML mode, edit posts straightly in Compose mode. Use inbuilt editor–apply web-safe colours to post text, click B and I icons to fill text with red, green, blue, bold and italic words.
Replace custom, carefully chosen and matching typeface font with Arial or Trebuchet and make font-size tiny. Fill your posts with animations and music players (autoplay is fine). Ignore carefully styled figure tag with bottom margin and place image straightly to the post body. Text will stick perfectly to the edge of the picture or video, no spacing will appear in between.
It is good to remove contact form with well-styled inputs and place instead some third party widget containing contact form.
On responsive templates it is very good to use images, videos and widgets with fixed size (in pixels). Upon resizing the window (or on smaller screen) these elements will overflow the box they sit in. Never use predefined markup for YouTube or Vimeo videos, paste instead of video id the whole code with fixed width and height to post body–always ignore carefully calculated in percents iframe markup.
Another thing to do is to define a number of posts per page as 20-30, just to make it endless and annoying for reader. Good step is to add to sidebar 20 or more unstyled widgets.
Well, the list of how to make a blog looking horridly may continue infinitely. Just, a question: whether it is worthy doing?