I use Coprone's ENB, you should try it too imo it's really good.
When taking pictures use +&- for zoom. Using lots of zoom really helps pictures look good.
RP Stuff
Read the rules obviously.
When buying cars or parts you can use the shops made by people or just find the part you want online and use that price. Don't use "from a scrapyard" and then make up a price, unless it was from a scrapyard with proof.
Take real amount of times to do things, you can't build a car completely in a day.
Research prices for paint etc
That should do hopefully.
