Direct mail is a traditional form of marketing that has become much less effective over the years, to a point where many companies have abandoned it.
Once people spoke confidently about getting a 1% response rate or more. Now in a lot of cases 1/10% - 1 in a thousand - is considered acceptable.
That doesn't mean give up on direct mail. But it needs to be intelligently assessed. With increases in postage costs, 50 cents per piece (including all costs) is a realistic estimate for postcard mailings, and it goes up from there for brochures, sales letters, broadsheets and so on. That adds up quickly.
Absolutely if you are going to do direct mail you'd better have an excellent website as that can easily double or triple your response rate. Also you need to have in place a slick process for handling leads, so you don't waste the response you do generate.
Other key factors to consider:
1. The list. Who do you send your piece to? This is hugely important, if you are spending 50 cents per piece or more, you want to minimize the waste and maximize the return.
Anything you can do to narrow down or select out the likeliest prospects is going to pay off.
2. The offer. I wrote a post on this subject. Offers are important in most marketing but they are hugely important in direct mail. Select an offer that will appeal to your potential buyers, and make sure they see it right away when you look at your piece.
The design, type of piece, how delivered, etc. - everything else having to do with your direct mail marketing - is less important than these two factors. A great design, excellent copy writing and so on, help. But they are not the deal breaker or maker that the list and the offer are.