When i started exploring the route planner did not work for more than 100LY, so you needed to open the map and plan your next section after 100LY which in my hauler where roughly 4-5 jumps at that time (23LY if remember correctly).
There were no tools or journal log either, so i personally wrote down every system i visited on a paper and planned my route by selecting waypoints from the GalMap and writing them down so i can find them. That was the normal way of traveling - from waypoint to waypoint.
There where no tags visible, so you didn't know if someone already explored the system. They introduced this just before Horizons and i need to admit that few days after that i was in no mood of playing as some of the best systems i found where already discovered and tagged.
There where no way to find out the type of the planet from the system map. This came some time later after a CMDR effort of figuring the use of the background music/noise inside the map. After that it was a breeze to find WW, ELW and AW. The terraformable HMC's where still pain to guess.
There was and it's still there a way to check if the system you are jumping in is a possible close binary. I used this a lot, nowdays... nope.
In order to explore a system, you needed to fly to every body on the system and scan it from a close distance. Now this is obsolete due to the FSS, however you still need to do it in order to map the body with the DSS.
I need to say that if you wish to map a whole system now you will lose more time than it was before the FSS/DSS. I remember when i found Sigma Orionis and decided to explore the whole system - it took me 5 hours to do it. For those who don't know - the system is bigger than Alpha Centauri.
Nowdays i also sometimes tag only the good stuff in a system, but that's when i am traveling quickly to somewhere. Once i reach my destination i lower the pace and start using the FSS on every system even if it's just icy bodies with a brown dwarf main star. It is an unexplored system after all.
I lose more time now as sometimes i decide to hunt some biological data on the surface. Finding the bacterium patches is pain but i am starting to get used to it and to find them more quickly.
For me the "cheating" is exploring with a Fleet Carier and having UC on board where you can dump your data almost immediately after finding it. But i think that's an unpopular opinion.