OK, so this is a professional opinion. First, I never tip, unless for cover, if I am losing. I rarely tip during the session but only at coloring up and then do so "appropriate" to the win.
If you are a recreational player then here is a tip on tipping that you should find useful.
Let's say you want to tip a dollar in addition to your $10 bet so you put a $1 in front of your bet. What you have just done is give the $1 to either the casino if you lose or the dealer if you win.
So, now let's do it another way. Same situation only this time I put the tip $1 on top of my $10 bet. Now I retain control of my dollar. If I lose I gained nothing and the casino takes my money. If I win, however, I give a $1 to the dealer and keep my original dollar. The dealer still gets a tip and my tipping cost is cut in half.
BTW, tipping a $1 on a $10 bet is giving an ADDITIONAL 10% advantage to the house/dealer. Even doing this on a $25 bet is an additional 4%. The casino had less of a 1% advantage if you are playing basic strategy before you helped with tipping.
You cannot win very long at this level.
Now, I am a very generous tipper in other where the people have more control over what they can do to provide service. Not so much at casinos. Dealers have very narrow protocols to follow and tipping them to "help" me could be confused as collusion and we could both become inmates. Not ever doing anything illegal.
What action is it that a dealer can do that you would describe as good service.
For me, it is only place the cut card deeper in the shoe/deck if he has that choice. Dealing fast is always a benefit as it allow me to play more rounds speeding up my path to the long term for the law of large numbers.
Otherwise, intentionally making payment errors, dealing other than the approved protocol or any other variations are illegal at worst and will get them fired and you kicked out as a cheat at the best.
Other things are being friendly, polite, funny, entertaining etc. but then so can the workers at McDonald's and I don't tip them.
Here is a novel thought, why don't the casinos pay their dealers (workers) a fair wage and quit depending on free money from their consumers to pay their employees. In gambling, the casinos part is known as a free roll. Or change the concept of tipping when I win to include a rebate when I lose?