If you means to play in Standard Construct tournament (like FNM) at your local stores, you need a minimum of 60 cards, NOT 40. Minimum of 40 is for Limited (Draft or Sealed) only unless your local stores have different rules which is rare.
Assuming you need 60 cards, you'll need a lot more.
What's the win condition in your deck?
1. Via damage: you only have 4 creatures that can attack. Clone is another option but if you use it to make a blocker, then you are not attacking. Doesn't help. Yes, Liliana's Caress can deal damage but ONLY when your opponent discard AND when Lilana's Caress is on the field.
You have Stormtide in your sideboard. Without any mana acceleration, you need minimum turn 8 to play. You may not have turn 8 with your current deck construction ...
2. Mill: you have 4x Traumatize and Jace's Erasure in sideboard but that's it. So not likely to win via mill but more for deck interruption. If you are going to deck interruption, 4x Traumatize is too much.
- Since I strongly believe you need 60-card not 40-card decks, you can add a few more creatures in your deck. One thing to keep in mind, Wall of Frost is not the best creature in Standard Construct. Against weenie deck, it can only blocks one creature when your opponent swarm you with 6x 2/2 soldiers or goblins, you are still dead. Against other control deck, they don't attack until they take care of your Wall (via unsummon or Doom Blade etc). Against Red Deck Win, they swarm + burn for fatal.
- When you decide what you need in your deck, ask yourself HOW you want to win. Then choose cards which will get you to your goal. Anything else, don't put include since you have limited slots.
- As for side board and main board control cards (like unsummon and Mind Control), you need to understand what you need to control before you know what kind of control cards to use. In order to know this, you have to study what other people use. If most people at your local store use creatures heavy deck, global removal like Days of Judgment, Black Sun's Zenith maybe some better options. If most people favour red or green deck, Flashfreeze is better than Cancel. If most people play control deck, Mana Leak and Spell Pierce will likely be better than Cancel.
Leyline of Anticipation: there is not that many cards you want to flash in your deck. You can flash creatures but that means they are blockers which doesn't help with damaging your opponent's life. The best I can think of is Mind Control. But Mind Control works the same without flash as long as your opponent's creatures don't have haste. The few Standard Construct worthy haste creatures are Goblins which can swarm you to death before you have a chance to Mind Control. Another is Vengevine which is usually in green ramp and again, can get you before you get 5 mana to Control. Even if you keep the 3 copies of Mind Control, it still doesn't worth it to put in 4x Leyline to help 3 cards when the 4x Leyline CANNOT win you game by itself. Remember, it is only good if you get it in your opening hand, any draw to Leyline is a total waste of mana. And if you don't cast it, it is a dead card in your hand. There is no good scenario either way.
Since you have a budget to your deck, I don't want to suggest cards out of your price range. Re-post or update your deck list with cards you have for a 60-card deck, then we can look at it again to see how to improve it within your budget.
Experience. I have been playing since Ice Age. I have been playing competitively since Time Spiral and also plays a lot of causal games with friends.