1.Coding: if you see any code that is un-necessary, you can delete it or if you see any similar code that they write twice, you could delete it and combine then into one function. For example, if you write style for each tag, and those styles are the same, you should write one class in CSS and connect to it.
2. Comments: If you already understood the code, you should delete the comments in your code because it is not necessary anymore.
3. Create thumbnail for picture: If you have a big picture, and you put it on your blogs. That makes your blogs load really slowly because it takes time to load the full picture. You should create a thumbnail for that picture and link it to original picture. If that picture is not necessary for your post, you can only have a link to it. By doing it, your blogs become lighter and faster.
4. Widget, function: As I mention in previous post, widgets can become a main reason for blogs loading slowly, so if it is not very useful for your blogs, you should remove it from your blogs.
5.JavaScript: You can write all your JavaScript code in to 1 or 2 files and connect to them by using src link.
6.Flash: As I said, you should not use flash for your blogs. It usually takes too much time to load.