Kind of expounding on the “Follow Your Guide!” remarks
1) Stay BEHIND your guide. It they stop or slow down , you stop or slow down . As others have said , they have local knowledge and are also watching fish and other signs of current . If you get in front of them you may drift into a current before they can warn you . Dozens of times around the world I have seen divers stay in front of the guide most of the dive and greatly increase their risk of something going wrong. In Komodo a few days ago a newbie got not far off the wall at all while waiting for group to exit swim through, nearly got swept away and burned 1/3rd of tank in 5 minutes swimming back with help from DM. It really wasn’t even a stupid mistake on his part , he just got a little far off the wall and took a minute to realize current was pulling him away. Often there is somewhere to hide out of the current ot otherwise slow down (don’t swim against current 5 feet off reef or you will just burn through your air )
2). Stay at same depth as your guide . Newer divers in particular sometimes think shallower is safer —sometimes not true . Currents are often slower closer to reef —if you are 10 feet off the reef you may be drifting faster than the guide
3). Along the lines of number 2, stay the same distance as your guide away from the wall/reef (especially if they are close , you are close ). There are also some sites in world where it is safer away from the wall but usually that will be mentioned in the briefing (in Palau this is in some location specific dive briefings , haven’t heard it come up in R4 ).
4). As said before , listen during dive briefing . Was in Palau with a a guy with 1,000+ dives who wasn’t paying attention during briefing. He didn’t follow DM when DM was trying to avoid a known upwelling and got swept over corner (and whole group had to follow and come up after 15 minute dive in a downcurrent )
All of that said , just pay attention and follow your guide. If you do that you should be fine .
One last bit, pay attention to your ears also. Even if you think you are swimming up, if ears need equalizing you are moving down