1. Produce a top 25 xxxxx list in whichever niche you are in (This can easily be done by just Googling 'Top Tips for xxxxx' and then choosing a selection of the tips to create your list - obviously anything you use should be rewritten in your own words.)
2. Create a blog post with the first 10 tips (make them some of the really good ones).
3. At the end of this list add an opt-in box with wording along the line of "If you would like to see further top tips, add your details below."
You can then either send them to an unlisted page with the remainder of the tips or even send a PDF with the information.
One of the strengths of this is that you are supplying value up front before they have committed to anything, and therefore the reader will be that much more likely/willing to give their details to you.
Good marketing is about getting rewarded for providing value, and this method very much uses that ethos.