Each new generation of Pokémon games has at least two different versions. The fact is that capturing all Pokemon in only one of the versions is not possible, which greatly complicates the achievement of the final goal, namely: "Catch them all!". If you are a true collector who hurts to look at an incomplete Pokedex, with a little patience and planning, you can become the greatest Pokemon collector.
Steps
Method 1 of 4: Capturing Pokémon

Step 1. Choose a target
By focusing on one Pokémon, you'll know which items to grab, which Pokémon to group, and what tactics to use.

Step 2. Decide on the group
To catch Pokémon with low health indicators, it is worth bringing in a low-level group. For strong or legendary Pokémon, you will have to use your best Pokémon.
In a regular game, it is customary to exhibit a Pokemon, the element of which has an advantage over the enemy, for example, fiery versus grassy. Since a Pokémon that has fainted cannot be caught, you can choose a Pokémon of the same element as your target

Step 3. Take care of your equipment
Not a single collector has the right to call himself a master if he did not have the necessary tools for work with him! A great Pokémon hunter like you needs the right Pokeball to catch his prey. You can purchase them at Pokémart or the Pokémon Center. Each new version of the games has its own characteristics, but you should already be familiar with the main Pokeballs:
- Standard Pokeball
- Superball
- Ultraball
- Masterball
- Safariball

Step 4. Catch Pokémon through random fights
The most common way to get new Pokémon is to participate in randomly generated battles that occur as a result of your character moving through specific locations. Most often, Pokémon can be encountered in the following places:
- High grass
- Water (when using the "Surfing" ability)
- Caves
- Fishing

Step 5. Loosen up your goal
During a random encounter, your group of Pokémon will have to face a wild Pokémon. With full health, Wild Pokémon are more resistant to being caught, so before throwing a Poké Ball you need to weaken your prey first.
If your target continues to resist being caught, try applying a status effect such as sleep or paralysis to it to increase your chances

Step 6. Don't give up
It can take hours of random encounters to find some of the rarest Pokémon before you finally get lucky.
This activity, often referred to as “grind,” can be done more effectively by playing your favorite music, audiobooks, or movie

Step 7. Name your new Pokemon
Be sure to check out the new Pokedex entry to find out something interesting about your new friend.
Method 2 of 4: Evolving Pokémon

Step 1. Catch the lower forms of Pokémon
They come across much more often. You can pump them so that they gain experience (XP) and increase the level. Many Pokémon evolve after reaching a certain level, which means you don't have to catch its more advanced form.
Your Pokedex will keep the previous evolution as "caught"

Step 2. Level up your Pokémon
Some Pokémon, especially high level Pokémon, can only be obtained through evolution. Pokémon like Charizard and Blastoise are extremely rare in the wild.
To level up your Pokémon, fight other Trainers or Wild Pokémon. Winning battles will allow the Pokémon to gain experience points (XP), which increase its level

Step 3. Find, buy or win evolution stones
Some Pokémon do not evolve by leveling up. Pokémon such as Pikachu and Clefairi evolve only after using special items called "Evolution Stones" on them.
- Use the stone wisely - some of them can be quite expensive.
- These stones can be found throughout the game, but most of them will be available after completing the main campaign.

Step 4. Use the stones of evolution
Select an item from inventory. After that, you will be prompted to choose which Pokemon to use the stone on. Once you select a Pokémon, the evolutionary process begins, transforming your Pokémon into its more adult form.
Method 3 of 4: Swap Pokémon from other versions of the game

Step 1. Catch the Pokémon exclusive to your game
They will come in handy later when you want to exchange with friends. Both versions of the games have a unique Pokémon that is not available in the other version.
It would not hurt to catch two rare Pokémon so that one of them can be kept for yourself and the other one can be reserved for exchange

Step 2. Find a person playing a different version of the same game
If you know someone who is playing a different version of the game, talk to that person and get everything ready for sharing.
If, for example, you play Pokemon Black, look for someone who plays a different version of the game, that is, Pokemon White

Step 3. Look for coaches who have already completed the game
Passing the game unlocks full access to all Pokémon in their version.

Step 4. Trade Pokémon with another player
Connect the two devices using a dedicated cable (for Game Boy) or Wi-Fi connection (for DS / 3DS consoles). To start trading, log into the game and head to the Pokémon Center.
- Ardent collectors sometimes collect two of each type of Pokémon in order to make the final trade with another player. This way, you can get hold of all the Pokémon available in this version of the game.
- If you don't know who to trade with, grab a different version of the game and play it on another Nintendo game console (Game Boy, DS, 3DS).
Method 4 of 4: Other Ways to Catch Them All

Step 1. Win the Pokémon League
On your way to victory in the League, you will meet Pokémon who can be recruited into your ranks. In addition, battles will increase the level of your group, thereby expanding your collection through evolution.

Step 2. Raise a new Pokemon
This method is especially useful if your friend doesn't want to give away Pokémon exclusive to their version. Raising a Pokémon will allow both of you to add it to your Pokédex.

Step 3. Exchange or return rare Pokémon
Please note that some rare Pokémon can only be encountered once per game and cannot be raised. If your friend does not want to part with such a Pokémon forever, use the reverse exchange. Even if you return your friend his Pokémon, your Pokedex will still register him as captured.

Step 4. Find out what activities you can take part in to catch a specific Pokémon
Gotta Catch 'em All events are your chance to get your hands on a couple of rare Pokémon to add to your collection. This is where the game guide can come in handy, although a list of activities can be found online as well.
- Some online stores sell Pokémon coupons (for example, on eBay).
- In such events, for example, you can get hold of Togepi, Evie, Lapras, as well as Pokémon Fossils.

Step 5. Examine the game thoroughly
Remember that some Pokémon are not found in your version. But don't give up hope. Some Pokémon can only be found in locations that you have not yet explored.
Advice
- Be nice to your friends and don't forget to thank them for their help.
- Take breaks from time to time. Sitting for long periods of time can negatively affect your health.
- Some Pokémon may already be in their perfect form. They are excellent breeding candidates.
- Your friends may not always be able to exchange with you. Sometimes it will be easier to buy a different version.
- For capturing all the Pokémon available in the game, you will receive a reward. The reward will depend on the version and generation of the game.