Theme change = formatting change?

I hav a problem.
Since I change to my own made template. My format / styles changed!

I want to fix something abt break line.
I love the default template of WP like this.
when I use the ol/li: (Default template is tidy one)
1.xxxxx

2.xxxxx
xxxxx
PICS

3.xxxxx

But since I changed to my other template.
It shows:
1.xxxxx
2.xxxxx
xxxxx

PICS

3.xxxxx

The line break shows ridiculous and ugly.
How can I change my CSS style or what can I do abt it?
Someone said change the formatting.php from $br=1 to $br=0..
Its not working for me and it made some error!

So I juz want a right way to do it.

Can anyone help? ><