Here's a comprehensive Deck Building Guide for Pokemon TCG Pocket:
Understand the Basics
•Deck Size: Your deck must consist of exactly 20 cards.
Card Types:
•Pokémon: Include Basic, Stage 1, Stage 2, and Pokémon ex.
•Trainer Cards: Divided into Items and Supporters, but no Energy cards since energy is provided via the Energy Zone.
Core Principles
Type Focus:
•Concentration: Build around one or two types for better energy management. This doesn't mean excluding all other types but focusing your strategy on a primary type.
•Type Matchups: Consider the meta and common decks. If Fire types are popular, including some Water type Pokémon can give you an edge.
Balance and Synergy:
•Offense and Defense: Include a mix of Pokémon for attacking (high damage outputs) and defending (high HP or beneficial abilities).
•Synergies: Look for Pokémon whose abilities or attacks complement each other, like energy acceleration or setup for big moves.
Trainer Card Utilization:
•Items: Use for immediate effects like drawing cards, healing, or searching for specific Pokémon.
•Supporters: These are powerful but limited to one per turn. Cards like Professor's Research or Sabrina can be game-changers if used at the right moment.
Deck Construction Steps
•Choose Your Core Pokémon: Start with a strong Basic Pokémon or a Pokémon ex that dictates your strategy. For example, Mewtwo for control or Charizard for direct damage.
Energy Management:
•Energy Distribution: Since you get one energy per turn, decide if you'll focus on quick, low-energy attackers or invest in setting up for a high-energy payoff.
•Support Pokémon: Include Pokémon that support your strategy, whether through evolution, abilities to disrupt opponents, or to provide additional type coverage.
•Evolution Strategy: If using evolutions, ensure you have a balance between Basic Pokémon and their evolved forms to not be stuck without options.
Trainer Cards:
•Search: Cards like Poké Ball are essential for consistency.
•Disruption: Supporters like Giovanni can remove threats or change the game's flow.
•Consistency: Include cards that help you draw or shuffle your deck for the cards you need.
Counter Strategy:
•Weakness Coverage: Have a plan for dealing with common type weaknesses in the meta.
•Tech Cards: Include one or two cards that can counter popular strategies or deal with specific threats.
Testing and Refinement
•Solo Battles: Use these to test your deck's consistency and effectiveness against AI opponents.
•Community Feedback: Share your deck ideas online for feedback or to see how similar decks perform.
•Adaptability: Be prepared to tweak your deck based on what you learn from gameplay or new card releases.
Advanced Tips: 
•Pack Points: Use these wisely to fill gaps in your deck or to acquire cards you know will fit your strategy.
•Wonder Pick: Focus on packs from sets that contain cards you're interested in for your deck.
•Event Participation: Events can introduce unique cards that might redefine your deck-building approach.
Final Considerations
•Deck Archetypes: Understand common archetypes (like Rush, Control, Combo) and how your deck aligns or diverges from these.
•Consistency vs. Power: Sometimes, a deck with less powerful cards but excellent draw and search capabilities can outperform a deck full of high-damage Pokémon.
•Adapt to Updates: The game will evolve, so keep your deck adaptable or ready to rebuild based on new cards or mechanics.
Building a deck in Pokemon TCG Pocket involves balancing your strategy with the game's unique mechanics, like the Energy Zone, and the competitive landscape shaped by the community and updates. Remember, practice and adaptation are key to success.