What's the best way to indicate in writing that someone is a lawyer?

Including ‘Esq.’ is not pretentious and is perfectly acceptable or appropriate.
I think I know what you mean, though. The fact that some attorneys use it, while others do not, probably makes the matter somewhat confusing. I will say, however, as a law student, it is not pretentious.
“The form of address Esq. is not used in the first person. It is used only when the reference is in the third person, such as addressing an envelope, making a formal introduction, or on business letterhead. Esq. is never used with any prenominal form of address, such as Dr., Mr., or Ms.. Thus, John Smith, Esq. or Mr. John Smith would be correct, but Mr. John Smith, Esq. would be incorrect.”

Esquire is the accepted method, but you made me curious when you asked if it was appropriate for women as well. I checked the online dictionary and it says yes, good for women as well.

I would stick with that.

By sounding pompous, clinically detatched, and snidely threatening?

@mammal: I meant if I’m writing about someone else. I thought that was obvious by now!~

I don’t know what the “best” way is, but I suppose that judgement depends on the audience, and why they are indicating their lawyer status, and what specifically they are indicating. For example, particular education degrees, the fact they are legally representing someone in a case, or are retained by someone, or that they have passed certain bar exams, or they practice in a certain area, or whatever.

I don’t see that “esquire” has anything to do with law. (Here’s one definition of ‘esquire’.) (My guess is many Americans have no idea what “esquire” means, and I suppose many of those think it’s just some weird invented “holier than most” proclamation.)

“Attorney” is an acceptable title.

Now, that seems like something they would include in the education program. I oversee a paralegal program with about 60 lawyers. As academics, for the most part they use their first and last names and JD. I don’t know how they identify themselves otherwise.