2. Camp often, it's cheap, restores entire party, and provides you a chance to check if merchants have a new tier of gear available for sale, upgrade weapons at Rajesh, and make useful food. So keep at least a couple Camping Supplies handy, if you forget and run out, no problem - use your Traveling Merchant to buy more.
3. Check merchants often for latest Tier of weapons, armors, and potions.
4. Upgrade your weapons to +3 level soon as possible, upgraded weapons do far more than just increase your damage, they also increase other stats such as Max HP, Max MP, Defense, Magic Defense, Luck, and more depending on the weapon type. Upgrade!
5. Rings are a MUST to survive, otherwise your characters will get one-shotted by later bosses. Remember: White Rings to protect against magic and Gold Rings to protect against physical damage (and light and earth magic). When you reach level 30, be sure to buy Epic White Rings and Epic Gold Rings. Early on White Rings will be too expensive so starting with Gold Rings is a good way to go (especially in Goblin Caves which has lots of Physical and Earth damage) until you can afford White Rings.
6. Craft Armor at Rajesh. Some of the best armor is available through crafting : White Armor, Gold Armor, and Cloak of Vampirism to name a few. The colored stones needed for crafting armor drop as early as the first boss and if you have the wrong colored stone for the armor you want you can change the color for the cost of one crystal at Rajesh.
7. If you are under-level or under-geared for a quest area, use your Portal to World Map which will teleport you near the Lacuna Dungeons where you can run some dungeons for experience, gear, crystals, etc. When you're done leveling and gearing up you can take the opened portal back to where you left off. (Portals opened with "Portal to World Map" stay open through saves/exits, so you can take your time until you're ready for where you left off.)