What are you trying to say?
"Here is, in the garden, mother and Hanako and Masao with me looking at a picture"? "Mother, Hanako, Masao are looking at a picture with me in the garden"? "Mother, Hanako, Masao, and I are looking at this picture in the garden"? Do you even mean to mention "I" at all? Because you are implying it by saying 〜と〜と〜といっしょに as opposed to 〜と〜と〜はいっしょに.

I can, no matter what you're trying to say, tell you that you have をみています incorrect because you wrote みてをいます.

I'm trying to say, "Here in the garden, mother, Hanako, and Masao are looking at a book together."

Can you tell me where I erred badly and implied I am there too? Should I have written が instead of は? Also, it's をみています, not みてをいます？

I already told you where you erred with your implication. 〜と means "with." So 〜と〜と〜と一緒に means "together with ~, ~, and ~." So you were saying a fourth person, along with mother, Hanako, and Masao, read. Here, I assumed it was you who is the fourth person. If you had been talking about your father before uttering this sentence, it could have been "my father, along with my mother, Hanako, and Masao..."

And yes, the present progressive is ている, not てをいる.

And finally, who is mother? Your mother? If so, in English, you capitalize it as "Mother" (and thus I'm guessing you're not a native English speaker). If not, whose mother? The word is different depending on this. Finally, who are you talking to? Someone else in your family?

And you probably want to say that they were reading the book, not looking at it. よむ, not みる. Unless they were like "oh this is a pretty book in appearance but we're totally not reading it."

Assuming it is your mother and you are the brother of the other two people and you are talking to, say, your father,
にわにはおかあさんとはなこちゃんとまさおちゃんはい っしょにほんをよんでいます。
庭にはお母さんとハナコちゃんと正雄ちゃんは一緒に本 を読んでいます。

If you're talking to someone not in the family, you'd say はは, not おかあさん. If you're talking about someone else's mother to one of her kids, you'd say おかあさん. Etc. And that's not even getting into whether you should use the plain or polite form いる vs います at the end, etc.

This is precisely why so many of us say "give us context" for questions on this board. Japanese is highly context-dependent.

Should you not use 庭で here instead of 庭に, since they are reading in the garden?

Also I see why JohnBraden thought of using 見る as the verb, since he was talking about 絵本, not 本.
In Japanese, do you still have to use 読む with 絵本？
When I read JohnBraden's sentence I wondered whether 見る was correct or not since 絵本 is a word I have never really used, and have only really seen used with 見る as 絵本で見る～.

I mean, I would assume you can both look at and read a picture book (depending on whether the book has any text or not) but since I have never heard anyone say it, and have never said it in Japanese myself, I feel unsure.

I apologize if I wasn't very clear and I wasn't aware, until now, just how much context has to do with the way the sentence is written.

As an exercise, I was given a picture that had Hanako and her brother Masao sittting in the garden with their mother. They were all looking at a picture book. I was given a few words, such as "here", "garden", "okaasan" (current computer doesn't have Japanese characters-work terminal), both kids' names, "together", "picture book", "look" and finally "is/are-imasu". I was to write a full sentence, using all those words, to fit the context of the aforementioned picture. I understand it to be an exercise primarily in particle usage. None of the subjects in the picture are related to me in any way, but they all are related to each other. By that description, how badly did I goof?

Hey guys,

My friend saw a tattoo in Japanese today and when he asked what it said, the person replied "What's life without magic?"

He later asked me to write it down for him.. but my Japanese is terrible and my guess was 奇術が無い生活は何？

But as I was writing, he recognised the 無 character, saying that this came first?

What's JF's take on this?

He didn't just confuse the 魔 in 魔法 with 無 did he?
I can't think of any way that 無い would come first in that sentence unless it was broken Japanese, since as far as I know "Life without ~" can be written as ～のない生活 or ～のない人生.

Unless of course it is ok to say 無魔法 or 無奇術, in the same way that you can say 無意味...
I don't really have much experience using 無 as a prefix so I can't say for sure if that is ok.

I love 'elping you more than hanging out with my lassie at the chippy but this one, I sure ain't got no clue. Matter of fact, I ain't even got no clue what a chippy is, laddie!

If you start it with 無, you won't have a phrase in a "normal" word order.
無意味だよ、魔法のない人生なんて
無意味だよ、マジックのない人生なんて
I could go on without a hit. There is no way of verifying this, is there?

You used 奇術 but that means magic as in illusions or magic show.

It is not OK, I am afraid. We cannot place random nouns right after 無.

I thought as much.
Thank you for clarification! :)