[Toxaris]

Almost everything is better than PDF. A normal text based format as Microsoft Word, RTF, HTML, ODF, something like that.

There are various tools you can try, depending on your knowledge level and willing to have it as you want. Most here use Sigil for the final creating of the ePUB. Sigil works best with (clean) HTML. Some use Yutoh or Atlantis Word Processor. Those could be used if you have no real HTML/CSS knowledsge. However, you are then restricted to the layout they can provide.