伎俩 is always negative — underhanded or deceptive tactics. Never use it for positive skills. For neutral 'technique' use 技巧.
mistakes
Don't confuse 伎俩 (trick/scheme) with 技能 (skill) or 技巧 (technique). Similar pronunciation, but 伎俩 is exclusively negative. Note also that the 俩 here is read liǎng, not liǎ — this is the one compound where the alt reading lives.
