Don't be shy about checking your rating with the floorman. When you finish playing, ask him how much money he has you down for and what average he has given you. Once the information is in the computer, it's difficult to rectify things. The outlines below are an approximate guide to what a large hotel will give you based on your play. Bear in mind that many other factors also come into play.
Casinos prefer players that spend time at the tables.
You may want to consider setting up a credit line. The casino credit hosts can assist you with this. Basically it is the same process as applying for a credit card. You can also deposit a cheque or a cash deposit at the cashier's cage and draw against it at the tables. These three methods will usually garner you more comp credibility than coming across the table with cash.