Players always remain confused about which troops to be upgraded first after construction of laboratory gets completed. The answer is Archers because they are more valuable in longer run if you are very active player who often raids and turns someone else to rubble. These are 3 basic reasons to keep archer in high upgrade priority.
First, Archers are more powerful than goblins and barbarians. You might surprise by this because they have lowest health and has the lowest damage per second attack power when compared to goblins and barbs. Actually archers have the ability of attacking that no other troop does, and that is ranged attack ability. That simply means that an archer has a better opportunity to damage defensive buildings like towers or cannons regardless of their wall protections. Try comparing barbarians that need to break the walls first before they damage a single small pavement.
Additionally, archers never pick targets. Unlike the goblins that prioritize the resource building while they attack, the archer can hit any thing on their sight including walls. This gives archers an edge in destroying the base faster as compared to goblins that are picky because resource storages often placed deeper enclosed in the base fully protected. However goblins are not useless and they are the best if your strategy is to steal the resources. But you cannot deploy them without the support of other troops like barbarians or giants because they easily get crushed. In contrast, any army that has 100% archers will be able to take away any type of base with decent protections and sometimes gets 3 stars.
Lastly, Archers are the excellent troops for Clan Castle, because of their ability to hit from distance that is very dangerous. If they are protected inside the dozens of strong protective walls, you will have an army that can eliminate the enemy without any fear of getting hit back. It is really a deadly combination.
Consider this and the strategy will be more effective if you deploy a complete archer army for a low level Town Hall Base for 1 to 5. In contrast, once you reach the level 6 or above the Town Hall level base, you may want to combine other troops like giants, wall breakers or goblins with archers to have better strategy.
For more tricks and tricks, cheats and strategies, Clash of Clans Astuce, reviews for all games or downloads, you can find them on forums by searching them on Google. Do some homework out of game to get the edge inside.