I am not a UV or spray tanner myself but I am pretty familiar with the industry. Doubt I'll be much help but here's my two cents. Mild sperg warning.
I've heard a lot of claims that the lotions clients use help with their color, as far as UV tans. However these lotions can be very pricey. Designer Skin is a very popular brand, and I've heard a lot of praise for Hemp Nation tan extender (its also much cheaper). Personally, I use the tan extender daily just because it smells and feels nice.
For spray tans you obviously can't use lotion prior, but primer is recommended. Not sure about brand recs for primer, though. For spray solution, I've heard clients say the clear solution (it takes about 8 hours to a day to develop) looks less orange, but again, I have not spray tanned. This is in regards to VersaPro/Spa solution. On the flipside, VersaPros have like 3 different varieties of instant solution they can use, so I can't say which type your particular tanning salon could be using.