For starters, pretty know that the RH guide is usually high. As they have a vested interest in getting employees to jump ship (usually due to perception of being underpaid). However, in my experience, sometimes their guide is high and sometimes on target (like now, with the large changes in the employment market I've seen over the past year). If you go on indeed and look at comparable jobs in your area, what are they paying (what RH says, less or more), as that will give you a better market rate.
That all said, I would be curious as to what you are currently paid, as outside of some of the big 4 this year, I've not hear many people getting raises over 10%, and for most lower level staff, a 19k raise would be 20%+.
As far getting a raise, for starters, are you happy at your current employer? And are there any benefits that you aren't taking into account that you may have to give up if you do change (short commute, a true 40 hr work week, great benefits, etc)? As if you don't want to play hardball (with the potential for actual jumping ship, you are somewhat limited, as in you can present your case, but take what they give you). When I've had to make my case as an employee, I've usually done two things:
1. Pointed out where the market is, to the point of potentially having proof of other jobs with the salary you desire printed out. If your employer has posted other job ads with the salary listed and it is higher, that can be used as well.
2. Made the case based upon what you have done for your employer for the year, such as had great realization, billed XX, brought in clients paying Y, worked 2500 hours (When the stated goal is 2200 or something), etc. And some of these you have to work around (or just toot your own horn) if there is some sort of bonus program as well.