This all depends (as been said already I will expand a little) ;
How organized are you? Your assistant should be way more (organized)
How many "new" customers you onboard - If you have regulars only (or a high percentage of regulars - no needing verification etc) then an assistant is much a waste of profit
Pros - they can offload the burden of the daily admin tasks and you can solely focus on service (and quality of service). You will also avoid having to deal with the volume of calls
Cons - Cuts into profit 20-40% depending on who is helping / could cause miscommunication between you and the client (I.E, maybe a specific clothing request was not forwarded to you)
You should advertise on as many sites within the community as you can...TER, Date-Check, P411, and other "Escort" sites... I would avoid "Backpage" and the likes as you will be competing with quite a bit of noise on these pages and may not get proper placement or attention.... also depending on your rate, you may be in the wrong price range for certain sites.. i.e To high for Backpage
As mentioned Date-Check and P411 are a few screening sites, but you kinda need to know what you are looking at, as someone might say "i'm Date-Check" but if you don't at lest look at the profile, you may get yourself with someone who has an "account" on the site, but no actual providers vouching for them. So as for the screening sites, just make sure you can verify and access the information to confirm the person is legit
What do you want to "Do" in MD Besides us

(What are your interests - Running? Museums? etc...
Photographers? thats been debated before, but IMHO if you look hot in a selfie, or a low tech/amateur photos, you will be saved the embarrassing comments here that your photos are airbrushed in anyway... even if to hide blemishes, fix skin tone, etc, someone will find a way to say you don't look like your photos.. for some who might be interested in you, this could be a "no-go" comment if read...
2 pennies hit the floor pick um up if you want two