I had a personal injury lawyer client for a short time. As with any product or service, your keywords must be very specific. In your case, it would be personal injury lawyer.
Don't do like this client. Before I came along, he was bidding on "car accident" and that sort of thing. Almost all people who search on these terms are not looking for a lawyer. In fact, I showed the search term report that most were actually looking for information about an accident that occurred. This does many things to your campaign, none of them good. First, your click rate is low and thus affecting your Quality Score and this increases your costs. Second, if you get clicks, they are poor quality and convert at a much lower rate, if at all, so you just waste your money.
This client understood at first but then saw that the amount of traffic was much lower (although higher quality, number of sales virtually the same at one tenth the cost). He was only looking at traffic numbers from his campaigns before and after and decided he knew better and reverted back to his way of doing things. His thing was that no matter the cost, one conversion is worth thousands of dollars (often tens of thousands) so he figured it was worth the cost to get unqualified traffic. I disagree and urge you not to fall into that trap.
Yes, as suggested, don't be shy to spend. What I mean by that is not the budget but your bids. Don't be afraid to bid so that your ads show at the top. Be smart on HOW you spend. Learn about PPC, how it works and how best to take advantage of it.