This is because I've researched a lot before doing it and even if lots of people were saying how important it is to do it, I struggled to find practical info of HOW to do it! So I would like to share exactly how I did it, and hopefully this would be useful for people who have never done it before.
First of all I designed my promo sheets. They need to include some of your best images and your contact info on every page. Mine was intent to be directed to publishing houses so I decided to include only illustration with kids, animals and a sense of narrativity.
I've decided to not include more than 3 pages, manly for costs reasons but also because I read that's what people usually do. I made it an horizontal design because my images are mostly horizontal and it was easier to fit them in the page. After struggling a bit (how can I fit vertical and horizontal formats in just one horizontal page??) this is what I've come out with.
The first page includes 2 images from Goldilocks story and 2 from Red Riding hood. Including more picture from the same story is important so that I can show I am able to give continuity and a sense of narrativity. (click on the image to make it bigger)
This page is focused on pictures that show backgrounds, animals and people, in particular kids!
The last one is a collection of picture that I reckon might be found interesting for a publisher. That includes a picture from Hansel and Gretel and come animal characters.
I stapled the 3 pages together and on top of that I put my cover letter separately.
I designed my cover letter with my own personal letterhead which includes my logo and my contact details. I quickly introduced myself and explained that I was sending an illustration submission. I kept the cover letter very short (one page only!) since I didn't really know if it is something publishers actually read. However, I think it's a matter of courtesy to explain why you're sending something to someone so I would recommend to write a brief introduction of your work.
I've put them in a big envelope because it's much more professional to send them flat and not folded. This is what the whole thing look like.
On top of that I added a SASE card. This is something optional but useful to get feedback from publishers so that I'll know if they like my work or not. I've addressed the card to myself, I've left some room in the top left corner to handwrite the name of who is sending the card back and some multiple choice answers. My answer options were:
I like your illustration samples!
Please send me a full portfolio
I'll keep your samples on file
Please send me new samples periodically
Unfortunately your samples are not appropriate for our current needs
I've left some space for some comments as well to invite publishers to write further feedback.
Basically they need to just cross the proper answer and put it directly in the mail. Easy!
Here a picture.
To print them, I've used the website Ready, steady, print which is Australian and quite fast. I used them before to print some business cards and the quality/prices were good. Actually, I made a mistake when I ordered these cause I stupidly choose a too thin paper (only 100gs, damn it!) so make sure to choose a paper that is thick as a postcard, or similar. I guess 230gsm would be enough.
Since it was the first time, I've decided to focus on Australian publishers only and I made just 22 of these promo mailers. Not many, I know, but I wanted to see how it would have been received before making dozens. Still, this is something that can be quite costly. Here it is what I've spent (prices are in Australian dollars):
25 Envelopes $4.95
22 SASE card stamps $13
22 parcels shipping costs $26.40
250 SASE cards $56
22 cover letters copies + 22 copies of each illustration page sample $17.60 (I managed to get them super cheap in the printing room of my school! Otherwise this would have been the most expensive thing in my list)
TOTAL= $ 117.95
I reckon it's ok for a promo. Also, I still have lots of SASE cards that I can still use in the future.
PS= I strongly suggest to use InDesign to design your sheets, instead of Photoshop or any other software.