1) take --- to heart = take --- seriously ex). I've taken the old saying to heart.
2) do-it-yourself fan = なんでも自分でやる主義の人
3) already made = 既成の
4) varnish = ニス、ニスを塗る
5) I see --- = ~みたいだね。
6) I'm all thums. = 自分は不器用だ。
7) not so hard as you might think = 思ったより難しくない
8) nail = くぎ
9) I might ask you. = あなたに頼みたいくらいよ。
10) put the parts together = 部品を組み立てる
11) He prefers to make things. ⇔ He prefers not to make things.
12) Did you make that furniture? No, I bought it already made. (既製品を買ったの。)
13) What have you got there? = 何持ってるの? それ何?
14) Oh, these are som eparts for making a desk. = うん、机を組み立てるための部品だよ。
15) Making things is fun, isn't it.
--Yes. And besides beting fun(楽しいだけじゃなくて), it's interesting, too.