So, you're thinking about making your own ketubah?
DON'T DO IT
Talking you out of it will be difficult, but I'm going to try. (If you are reading this, you may be a hopeless case).
I know, I know, this may look like a conflict of interest, but I'm telling you this for your own sake. Truly. (Of course, I also happen to have a lot of great ketubot to sell you just over here....)
Seriously though, I learned this the hard way: You have a limited amount of time and energy in the lead up to your wedding and you have to decide how to use it.
Your wedding will be stressful enough without a huge project with an enormous amount of pressure that must be ready on a deadline while you are preparing to throw a party for not only your own family but your new in-laws and both sets of friends. The sheer number of details that go into making a wedding are overwhelming.
Choose what you take on wisely so that you can enjoy the wedding.
These arguments don't hold water:
Nothing suits our taste.
Once upon a time, there weren't many good options for a discerning couple. This is not true any more. There is a huge variety of beautiful ketubot for every taste. If you don't like my art, and you looked at the we-sell-everything judaica and ketubah websites, just do a quick search on etsy. There are many inexpensive hand-painted (but not custom designed) ketubot.
Buying a ketubah is too expensive.
I understand, really I do. Weddings are hugely expensive. Vendors jack up their prices as soon as their hear the word 'wedding.' For instance, I got my wedding cake for 1/3 the price because it was labelled a bat mitzvah cake. To see why ketubot cost what they cost read "Why are Ketubot expensive?"
Think about your time. Making a ketubah can take me between 45-70 hours. You haven't done this before, so assume it will take 70-100 hours. Spread out over a year, it doesn't sound so bad, but we both know that art projects need chunks of unbroken time. This will be in short supply over the next year. When you think of spending even $600 for a ketubah, think about that in hours. If it takes you 100 hours, to make a ketubah that you could buy for $600, you are paying yourself $6/hour, and that is assuming you already have all the supplies.
We want something more personal, not mass produced.
There are many limited run editions, meaning a ketubah is only reproduced a certain number of times. All of my ketubah collection designs are limited to 200 in any size. Each one is numbered, the text is set for the couple, and may be customized as desired. You want to add a poem? Is there a song that has meaning for you? This kind of personalization is included in my prices. When you buy from the artist, you are establishing a relationship with that artist. It is not impersonal at all.
You still want to go ahead, huh?
First of all, good for you. Ketubot are fun to make, a wonderful art form.
I couldn't resist making one when I got married. (And of course, I made the invitations, designed my wedding dress, our rings, the chuppah, the flowers, my husband's new tallis.... and we wrote our ketubah text and the wedding ceremony and program).
I had always loved illuminated manuscripts and had a lot of unfulfilled artistic ambitions. It seemed like a natural fit. Of course, I was a stressed out wreck by the time our wedding came around. I didn't have time for a manicure because I was too busy doing my flowers.
But maybe you are more organized and not working 70 hour weeks. I'm sure it will be different for you...
Go With Your Strengths
Don't try to learn a new media to make your ketubah. If you are really strong in ink drawing but have never really done much painting, don't try to learn a whole new skill set in time for your wedding. Stick with ink drawing. This will make your art more personal and make the project more manageable.
Outsource the Text
Unless you are literate in Hebrew and skilled in calligraphy, consider buying a printed text. The text is a huge amount of work. It usually takes me two days to do a completely custom text by hand. The first day is translation, layout (including making lines with a t-square and light pencil), then pencilling in the text. The second day is checking over the work, then inking, drying (so that the ink doesn't smear), then erasing all the pencil. It makes sense to outsource this.
Plan to make mistakes
If you anticipate that even the best of us can have a bad moment that destroys months of work, you will save yourself a lot of time.
Do the art on a matting, not on the same paper as the text. Go to a craft store and see what you can find. You can cut your own out of watercolor paper if the paper is important. That way, you don't have to redo the calligraphy if you spill some paint (or redo the decoration if you spill some ink doing the calligraphy).
Make sure you have the right tools
I have a page of art supply recommendations. Buy good paper (cotton or other archival material) and get several sheets of it so that if you spill ink, you don't have to find the right paper all over again. At a minimum, make sure you have a good ruler and triangle for layout. Making text follow even lines is pretty tough if you don't have a good line to start with.