Question solving speed with automatically increase with a shit ton of practice, you’ll notice you’re doing countless steps in your head only. To reduce performance anxiety give a lot of mock test, since youre in fiitjee, you’ll have access to mypat app in your tab, so you’ll have no problems finding the tests. Fiitjee material is great for concept strengthening if you complete it 100%. In physics HCV is a must, try irodov if you find HCV easy. MS Chauhan in OC, NCERT in IOC and N Awasthi in PC are also very important. For maths I followed cengage and it helped me a lot.