Hi.
The Ballad of Gay Tony came out with a special feature: misson scoring. It means that after each mission you getting percentage of it's completing. After completing storyline you will be able to replay missions to impove your score. Percentage depends on mission walkthrough time and several objectives. I want to tell you how to easy complete common objectives.

• Walkthrough time: this is basic point. When you walk through storyline first time, try to complete missions as faster as you can.
  
  
• Player damage: Some missions required you to stay with high health level. So first time playing try to take less damage. Also if you encounter vending machine or health kit, take it. Last thing: doesn't important how much damage you take, important how much health you have when mission passed.
  
  
• Accuracy (this objective take place in shooting missions): some missions required pretty high accuracy level, so here's few tips how to get it: 1) When replaying missions make sure you have some Sticky Bombs or RPG. Make few accurate shots and then use explosive to deal with enemies. Using explosive not affect accuracy. Now you can easy get 100% accuracy.
  2) Using gamepad feature auto-aim if you have one, otherwise use first tip.
  
  
• Headshots (shooting missions): Just make a certain number of headshots, someone may find it easy to use sniper rifle. In mission Chinese Takeout you need to kill hostiles only with headshots.
  
  
• Car Damage: In missions such as I Luv LC, Blog This!... you have to drive carefully.

Also I want to highlight missions Sexy Time, Ladies' Night this missions requries high flying skill. In Sexy Time you have to chase and eliminate moving targets using helicopter. It is pretty hard to do this on keyboard+mouse so I used gamepad. If you dont have gamepad the only advice: maximize your flying skill.
In mission Bang Bang you have little time, so you need to use helicopter. You can watch detailed walkthrough on YouTube.

And remember you have ability to replay missions AND! you don't need to complete all the objectives in one run . For example in mission Blog This!... you must keep car in good condition (0% damage) and drive very fast to beat required time. It's very hard, so on the first run concenrate on maximum speed, and when making second run drive slowly and avoid car damage.


Thank you for reading, ask your questions in comments. For detailed walkthrough use YouTube.