Ability and permission
私は日本語の本が読めます expresses reading ability. ここで本を借りることができます describes an available service. ここで写真を撮ってもいいですか asks permission. Potential forms and ことができる overlap in many contexts, but are not the same grammatical form as てもいい. Practise potential forms and ことができる.
Intention, schedule or decision?
行こうと思う expresses an intention; 行くつもりだ focuses on a personal plan; 三時に始まる予定だ describes a schedule; 行くことにした says you made a decision. These meanings can overlap: personal trips can also have 予定. Follow the question’s requested meaning, rather than assuming one word always wins. Compare つもり with 予定.
Four conditions
たら can introduce an action after a condition is met: 駅に着いたら、電話してください. ば presents a condition: 時間があれば、参加できます. なら takes a premise for advice: 京都へ行くなら、この地図が便利です. と often describes regular results: このボタンを押すと、ドアが開きます.
More than one conditional may fit a situation. Do not mechanically attach a personal request after と. Whether a request or intention can follow ば also depends on the subjects and whether the clause describes an action or state. Start with たら and compare the full sentences.
Follow the direction of help
私は友達に本を運んであげました: I carried books for my friend. 友達が私に本を運んでくれました: my friend carried them for me. 私は友達に本を運んでもらいました also has my friend carrying them, but makes me the recipient and topic. Direct てあげる offers to a senior can sound patronising. In the camera story, list the people and actions before answering.