My F1 visa expires in a month when I graduate. Should I get married before graduation, or apply for OPT and get married later?

I would advise to do both. For more info about the marriage process See link below

Thank you for tour question. In your circumstances I would focus on the personal decision. If you and your fiancé feel that the timing is right to marry then I would seriously consider marriage. That said, marriage is a big personal step so if you are at all uncertain wait. It sounds as though there really is no reason to rush anything urgently from an immigration perspective. If you do marry you would be eligible to apply for a green card. While I understand that students on F1 visas and in OPT status can receive heightened scrutiny we have handled a number of these cases and have never had a denial or even a second interview scheduled (actually in 15 years I have never had any visa denied, though as I tell every client that could happen tomorrow and their case could be the first!!). As with all visas the key is presenting a very solid "package" of evidence. Unless you have complicating factors such as a police history or negative "immigration history" filling in the forms is relatively straight forward. Where a lawyer can add most value is in helping you prepare a package of evidence that supports you application and in ensuring that there are no hidden complications in your case that need to be taken care of. I suggest taking a consultation that you pay an immigration lawyer for to go though your case and make sure there are no complicating factors. The focus of that session should also be to explain your personal goals to the lawyer and come away with an immigration strategy that helps you achieve those goals. While you can get free consultations finding an experienced immigration lawyer who you are comfortable with who will really spend the time necessary with you is paramount. I am sure there are excellent lawyers who offer free consultations but the immigration lawyers I know who are busy with a stong client base only offer free consulations to pro-bono clients who truly cannot afford their fees. I would look for a lawyer who solicits a lot of information in advance of your session so the session will be meaningful and valuable and is willing to spend "however long it takes" with you. As always, do ask lawyers for: their success rate, years or experience, client references, whether or not they practice other areas of law in addition to immigration law (immigration is a technical area of the law and someone who exclusively specializes on it may be most helpful to you), the number of cases for students in F1/OPT status they handle, which State Bar they are admitted to (check their disciplinary and complaint record with that Bar) and whether or not they are an AILA member (while not essential most immigration specialists are AILA members). Best of luck to you Mark