I recently started playing Splinterlands regularly in the Foundations format.
The card sets are much smaller compared to other collections like Arcana, Chaos etc so it is much easier to build up your portfolios.
Like building any other collection the first thing you need to focus on is getting your Summoners levelled up.
This is an important lesson I learnt the hard way in my Splinterlands journey. As you keep receiving more cards and levelling them up you will soon notice that until you have a levelled up summoner your other levelled up cards are useless.
If you are lucky to receive a lot of summoners from the reward box then you will save some funds which you can use to pick up the Legendary and Epic cards you do not find in your boxes.
My strategy is always to level up all summoners to Level 2 or 3 at least so I can field a decent team in any element. Then I will select a few elements I really like and level up the summoners to level 4.
I have already levelled up my Life element summoner to max level as my strongest cards are in this element. Next I will focus on building up my Fire and Earth element teams.