Important Points to Remember in Salesforce:

• We can track 20 fields for an object. We can’t track Roll-Up Summary and formula fields. We can’t create Roll-Up Summary field on User object.
• Capacity of picklist values are 300.
• Lenght of Check syntax: 4000 characters
• Length of the formula: 1300 characters. Size of the formula: 5000 bytes
• Only 10 Roll-Up Summary fields we can create per an object. We can create Roll-Up Summary field on parent object to perform operations on child object.
• Roll-Up Summary field performs 4 types of operations on child object. They are 1.Count 2.Sum 3.Min 4.Max.
• We can add 20 components for a dashboard.
• We can display 1000 records on each visualforce page.
• PageBlockSectionItem will take only 2 visualforce components.
• Standard fields are Owner, Name, Created By, Last Modified By, Currency, Division.
• We can’t create Look-Up or Master-Detail Relationship on User Object.