The current study examined the effectiveness of self-explanation prompts, visual signaling cues, and a combination of the two features on middle school students' (N = 202) algebra learning. Also explored were the differential effects of features for students with faulty conceptual knowledge (evidenced by a higher prevalence of making errors during problem solving) on learning. That is, we assessed whether students who make prevalent conceptual errors predictive of algebra performance differentially benefit from design features. Participants were randomly assigned to complete 1 of 4 sets of worked example assignments supplemented with self-explanation prompts (n = 51), visual signaling cues (n = 49), both features (n = 51), or neither feature (n = 51). Worked examples supplemented with either self-explanation prompts or signaling cues led to greater learning from pre- to posttest in comparison to the worked example control, with practically meaningful effects. The effect of assignments supplemented with signaling cues was moderated by error prevalence. Those who made errors more frequently demonstrating misunderstanding of algebraic concepts (e.g., the meaning of a coefficient) benefited significantly more from visual signaling cues alone than self-explanation prompts alone or control assignments. These findings highlight the importance of considering differential effects of design features when used in combination or in isolation, particularly for struggling students.