I took the risk between finding a yard & getting a horse that there would be space. I went up to visit the yard before I had a horse to have a look around so that I when I phoned to confirm I had secured myself a horse they were familiar with who I was.
I can't remember 100% what the procedure was then; probably sign a contract and leave a deposit (either half or full month's rent?) and then ask to make sure YO was there when horse arrived. It just made me feel more comfortable. In fact when Roxy & I moved to our second yard I left it to the YO to lead her to her new turn out field (being a bag of nerves myself, he was much more confident).
When we arrived on our first yard YO's car had broken down so I was there for 2 hours just watching Roxy graze. Probably a good thing as I was in shock that it was all finally real *insert poo pants icon*
It's mostly each yard to their own - but don't be afraid to ask questions. Most will be addressed by the YO when you get there but I was also asking questions to try & get a feel for the yard, i.e. in winter Roxy is not rugged, are there others on the yard of a similar opinion, or are they all over-pampered TBs, am I liable for damage if horsey damages fencing etc (there was a major difference on opinion on this between my two yards). Also, self filling troughs, i.e. or do you have to bring your own tough/bath? Again, a big difference in opinion between my old & new yard on this one.