Other than doing some of the start of the fjords before heading to Sentinel Island and delaying turning in some of the quests in the fjords, I didn't do anything special to try to level. The game shouldn't be balanced so that you become untouchable for parts of the game if you simply explore everywhere and do all the side quests, and getting to 2 levels above the final bosses shouldn't be that unexpected.
I stopped assigning stat points (to keep things interesting) and ended up with 39 unused points, but with the strong level dependence of combat it wouldn't be as easy to handicap yourself as in other games that become easy (ie remove or use lower level equipment, etc). That said I did get my fair share of challenge earlier in the game, so having some of the human sections become quite easy wasn't a big deal for a first play through, IMO. The moderate difficulty of a few boss fights and some of the dragon sections of the flying fortresses kept things from getting too monotonous.
There were a few topics about the lack of potions in the game, so I tried to conserve them, and use food instead at the very beginning of the game, etc. However, I found plenty of potions from loot, and did not need to purchase any. The only time I ever started using a lot of potions was when I tried entering an area with higher level opponents, which could be avoided by trying another area or quest first.
