The ASX 200 is set to face a challenging Tuesday, with a predicted 1.4% decline, despite positive Wall Street performance. This article delves into five key factors that investors should monitor. Firstly, the market's reaction to the US-Iran peace deal is crucial, as it could impact oil prices and, consequently, energy shares like Beach Energy and Santos. Secondly, the gold market is experiencing a surge, with gold futures up 2.3%, potentially benefiting ASX 200 gold shares Newmont Corporation and Northern Star Resources. Thirdly, the lithium sector is a hot topic, with PLS Group Ltd shares receiving a hold rating from Bell Potter, indicating a focus on the restart of the Ngungaju processing plant and future development studies. Fourthly, Mineral Resources Ltd shares are deemed a good investment, with a potential 16% upside, thanks to the US$765m lithium transaction and stable earnings from mining services. Lastly, the article highlights the importance of staying informed about broker notes and share market news, as these can provide valuable insights into potential gains and losses. In conclusion, the ASX 200's Tuesday performance is expected to be volatile, with a mix of positive and negative influences. Investors should carefully consider these factors and stay updated with market news to make informed decisions.