The Pokemon with higher Combat Power (CP) is more difficult to capture. First- or second-evolution Pokemon tend to have higher CP. To catch such Pokemons successfully, you may use items and additional Poke balls with higher tier
Colored Circles and Chances of Catching
When you tap and hold the Poke ball, colored circles appear around the Pokemon. This colored circle will be either green, yellow, orange or red, and those colors tell you how difficult the Pokemon is to capture:
Color of Circle
Green
Easy
Yellow
Slightly difficult
Orange
Moderately difficult
Red
Difficult
No Time Limit to Capture
In Pokemon Go, the Pokemon does not escape suddenly. The Pokemon does not take any actions until you toss Poke balls or use items.
Tips for Catching Pokemon
Summary
Incense and Lure Module to Attract Wild Pokemon
Razz Berry to Increase Capture Rate
Using Great Ball or Other Better Balls
Switching Off AR
Incense and Lure Module to Attract Wild Pokemon
You need to find a lot of Pokemon to increase capture rate. Incense and Lure Module help you see many Pokemon by attracting Pokemon to your location or to a PokeStop.
Throwing Razz Berry to a Pokemon
When you find Pokemon with higher CP or legendary Pokemon, throw a Razz Berry to them. The capture rate for the next Poke Ball gets higher. Razz Berry is unlocked at trainer level 8.
Using Great Ball or Other Better Balls
You may use Great balls or better Poke balls to have a higher chance of capture. As same as normal Poke Ball, these better ball types can be used in combination with Razz Berry.
Switching Off AR
Turning off AR is a simple but the best way to make tossing Poke balls easier. This stabilize the Pokemon in the center of the screen, and make easier to throw Poke balls at them.
Gain More XP by ‘Excelent’ Throw!
Bonuses for Skillfullly Throwing
If Poke Balls hit in the colored circle to capture Pokemon, you can gain bonus Experience Points(XP). The bonuses vary from Nice to Excellent based on the size of the circle, with the bonus XP increasing as the circle shrinks.
Capture Bonuses and XP Gained
Capture Bonus
Experience Points Gained
Excellent
100XP
Great
50XP
Nice
10XP
Curve Ball
10XP
Catching Pokemon
100XP
Catching New Pokemon
500XP
Spinning Pokeball and Curve Ball
By spinning the Poke ball before you throw it, you can add a curve to it. Using Curve Ball to capture gives you 10 XP bonus.