In League of Legends, securing First Blood and the 400 gold it provides is one of the most beneficial advantages for your carry to gain power early in the game. With that amount of gold, you can dominate your lane with a Doran’s item or build a key item earlier to snowball throughout the match. Not to mention the experience, gold, and time wasted by the enemy when they “count numbers.” Therefore, the impact of First Blood is substantial no matter what rank you are.
Here are the 10 simplest ways to secure First Blood in League of Legends:
Late Red Buff Steal

When on team 2, you can wait until 1:25 and then go steal the enemy team’s Red Buff. This strategy allows your team to steal jungle resources and secure early kills. This jungle steal becomes stronger when supported by champions like Braum, Blitzcrank, Thresh, or Pyke.
Secure Red Buff and Gank at Level 2

When on team 2, the jungler can gank immediately after finishing the first Red Buff. This way, the opponent will definitely be at level 1 (usually lacking escape skills) and will be caught off guard. This strategy is particularly effective with junglers that have strong engage abilities like Jarvan IV, Camille, Graves, or Kindred.
Additionally, you should ward the enemy’s Blue Buff to steal it if the opportunity arises.
Ambush in the Top Lane Bush
If you are using champions with strong level 1 combat capabilities in the top lane, you can wait for the opponent in the bush at the top lane and attack them as much as possible. Since you are the aggressor, you will trade a lot of health, and you may even take down the opponent if you handle it skillfully.
Ambush in the Bot Lane Bush

On team 1, if the jungler does not need help or starts with the Blue Buff, your bot lane duo can wait for the enemy in the bush and secure First Blood early. Conversely, on team 2, you can wait in the bush on the opposite side. This strategy is also more effective if you use strong level 1 support champions like Braum or Thresh.
Quickly Assemble in the River Area of the Top Side

To accomplish this, it is crucial to gain vision by warding the river at the right moment. With some strong invade champions like Lee Sin, Graves, Sylas, many junglers often tend to steal the bird camp and then gank mid lane. Taking advantage of this, you can gather 3 players at the top side of the map and overwhelm the opponent with crowd control to secure an immediate kill.
Pull Opponents to Check Vision Early Game

At the early game stage, many players often run to the bush between the Red Buff and Dragon Pit. Taking advantage of this, your team can ward that bush and ambush right under the Dragon Pit. If you catch them, the prey will either die or burn their Flash.
Top Laner Ambush in Bot Lane Bush at Level 1

This is an “ancient” strategy in League of Legends, but many people still fall for it unexpectedly. This playstyle is stronger if the support is a champion with strong crowd control like Nautilus, Thresh, or Morgana, and the top laner is a high burst champion at level 1 like Sion or Jayce.
Late Red Buff Steal

Similar to stealing the Red Buff from team 1, when stealing from team 2, you should also wait until 1:25 and then go in with 1 or 2 laners to secure First Blood. The chances of getting a kill are higher when using strong level 1 champions like Jayce, Renekton, Darius, etc.
Steal Blue Buff at Level 2

Right after finishing Red Buff, the jungler can immediately steal the Blue Buff if they see the enemy bot lane duo coming to lane early without helping the jungle. At that time, the enemy jungler is often at the Red Buff on the top side of the map or struggling to solo the Blue Buff – both are great opportunities to secure the Blue Buff and ambush the opponent for First Blood.
“Go All Out” When Hitting Level 2 First

If using champions with strong 1v1 solo capabilities at level 2 like Yasuo, Lucian, Ezreal, Jax, etc., you can take advantage of clearing minions faster than your opponent, hitting level 2 first, and ambushing the opponent to deal damage and secure First Blood.
According to ProGuides Challenger League of Legends Guides.