I agree with most of Johndoe's suggestions but want to offer a different take on the players card as well as add a few ideas.
In this situation, playing unrated or rated probably makes no difference. If you are a regular and play unrated, they will usually assign some sort of identifying placeholder type name to track your play. Often some identifying feature, or maybe related to a hat or piece of clothing or jewelry that you wear regularly. So playing unrated won't have the effect you are looking for. So I would go ahead and play rated. At a local type place playing rated looks more normal. Playing unrated and regularly stands out in that situation. And you can actually put that to work for you. Once you identify what little they give for table game action and blackjack in particular, if you see that comp amount suddenly stop, that can serve as a warning sign as stopping comps and points is often one of the very first counter-measures taken by casinos.
Short sessions and ending sessions after at the shuffle following higher bets are two of the top things you can do to try to gain some longevity. A lot of players think it is the bet spread that gives away card counters and it is to some extent, but the real culprit is retreating back to the small or minimum wager at the shuffle. Players parlaying wins, and chasing losses all raise wagers, but only card counters retreat back to that small bet.
Shorter sessions and exiting after larger wagers combined works wonders. And now I will offer another idea that works well with those two. That is spreading both ways, meaning do not start each shoe with your minimum wager. This is best explained with an example. Let's say you want to spread 1-8 at a $25 table. I would start with a $50 bet and if the count goes positive progress up to $200 like you desire. If the count goes into negative territory, drop down to $25. This means they will have to see the count go both negative and positive all the way to your max bet number in the same shoe to see the full spread. For the most part they will see a $50-$200 spread (1-4) until they really study it. You can even be more aggressive and play the first round or two at $75, and then get into your spread. There is a cost to this of course, but I have found it really adds to longevity.
The final thing I would recommend is to figure out just what betting limits fall within a casinos comfort level and stay within them if you can. This differs by casino and even different days and times within the same casino. But lets say they are comfortable with bets in the lower black range, but $500 draws extra attention (this is the case with many casinos). I would stay below that first threshold, if you can. If that is not a threshold you want to stay under, there is a second threshold, maybe $1000, maybe $800 that draws even more attention. You need to figure out what these are through trial and error and watching other players and tailor you game to limits that are within that casinos comfort level and better tolerated.
These are just suggestions of things that have worked for me and lead to some longevity. But of course, depending on the casino and how sweaty they are, it is possible nothing will help. Some casinos are a lost cause and just unplayable because of their tolerance levels. You will need to figure that out too.