1. I do not think you need 也 in this sentence. 也 means 'also','too''as well' If you want this *and* that :我想买这个，*也*想买那个 2.It depends.Both OK in most sentences. But 这*条*裙子 is better that 这“个”裙子 这(条)裙子不错，哪里买的？ 你穿这（条）裙子很好看。 这（条）裙子很贵。 In informal chat, without ‘条’ the sentences may sounds a bit causal, just a bit. On formal occasions, I suggested you use '这条裙子' And I think these are questions about Chinese (Mandarin), not Chinese(other).