Unfortunately you have to come to terms with the fact that the vast majority of what you put out will go in the bin, no matter how great they look. It's the nature of the beast. They say that a person has to see a mailshot at least 4 times before they even think about responding to it.
That said, it is part of the job and it has to be done. You have to keep at it and make sure you get the point across. It needs to be to the point, not too clever if its the first one you've done. You need to get the message across quickly and efficiently because if it's the first mailshot they've seen from you it wont be in their hands long, so you need them to get your contact details as quick as possible.
Then when you've posted to a certain area, hit it again, and again, and again,...
I'm just about to do a leaflet and we are agonising over what we are putting on it. I intend to add a small 'bribe' - giveaway to make it more memorable. And yes - the marketing has to 'touch' someone at least 5 times befre they bite. But it can be a mailer, a call, an email, a mailer, a letter etc. If you are lucky it will land on someone's desk just as they are thinking "I need a graphic designer..." or it has to have something about it that will make them keep it. Good luck!
I think a postcard is always a good way to do a quick mailer. Almost like a teaser. Could be like a holiday postcard almost... a good photo you've taken or an illustration. Short handwritten message... but you need to mail to a NAME not just a company and the hard bit - phone them afterwards and see if they received it. Good luck!
And you need your mailing to land on a Tuesday or Wednesday...and to follow-up the following week. Monday is too busy (talking about the weekend).
If you are going to do a 'trawl' round industrial estates the balloon would work. Go in find the right person, give balloon and go!
The postcard could be a teaser for the really clever idea. After you phone if anyone is slightly interested then you send the 'clever' mailer. But perhaps a month apart.
Wk 1 they get the card
Wk 2 you phone Group 2 get the card
Wk 3 nothing Group 2 you phone etc
Wk 4 the next mailer
Wk 5 you call again
If you choose about 10 people each week (no more) and cycle through you will be mailing/phoning only 10 people each week - and getting another 10 names for the next cycle.
Then it's a constant process but you never have too much to do.
I have to say I'm surprised at your question. If you send out details of what service or product your offering then naturally you need to talk about that!
However with any sales call, you don't immediately get on to sales. With any initial call you have to try and sound personable, its best to look at what they do before you call, so do a bit of background research and make sure what you offer will be attractive to them. If you get them talking in a chatty manner your half way there.