Use up as many red and orange tiles as possible! Red tiles will become rocks on the next turn, and orange tiles will become red tiles on the next turn.
Try to make the largest bears you can!
A large bear is worth more than several smaller bears of the same total size.
Since rocks impede a bear's ability to grow, you should try to prevent rocks from forming. If rock-forming is inevitable, the best place for the rocks is at the edges of the board or in locations where you know they won't affect the size of the biggest possible bear.
Taking certain teams of bears into an event can have a greater impact on your score. For example, Jazzy Bear gives bonus points for every J, A, and Z you play, and Zzz Bear increases the frequency of Z's on the board. If you take both of them into an event together, you'll have more opportunities to get those bonus points from Z's!
Some events also have bonuses. If you take the right team of bears into the right event, you're set up really well to score even higher!
Leveling up a bear increases its score multiplier ("final score bonus"). E.g., a bear that has a 20% multiplier will have a 30% multiplier if it levels up a few times. This multiplier can help to really increase your score. Can't beat a particular event? Try leveling up your bears until the score multiplier is high enough to make the event really easy!