Formally prove that these two premises are contradictory 
*

*Clever(a)  ∧ ¬Happy(a)

*∀x (Clever(x) → Happy(x))


So far I have something like this

[EDIT]
Thanks to Bram28 I got the correct proof.

 A: Don't use subproofs!
Just eliminate the universal and after a few more lines you are done.
Here's a tip:  Do not start any subproofs unless you know exactly what you are going to use those subproofs for.  In Fitch, there are only 6 reasons for starting a subproof:


*

*You are setting up a Proof by Contradiction (i.e $\neg$ Intro)

*You are setting up a Proof by Cases (i.e $\lor$ Elim)

*You are setting up a Conditional Proof  (i.e $\rightarrow$ Intro)

*You are setting up a BiConditional Proof  (i.e $\leftrightarrow$ Intro)

*You are setting up a Universal Proof  (i.e $\forall$ Intro)

*You are eliminating an existential  (i.e $\exists$ Elim)
Note that in your case none of these rules make sense: you are not trying to prove a negation, conditional, biconditional, or universal, and you are not eliminating a disjunction or an existential.
Also, to force you to think about what you are using any subproof for, make it a habit to follow the following steps if you ever do start a subproof:


*

*Start a (the) subproof(s) and write down the assumption(s)

*Write down what you what at the end of (each of) the subproof(s)

*Close the subproof(s) and apply the rule for which the subproof(s) was meant

*Finally, go back inside the subproof and think: how can I get to the last line of my subproof given what I have?
So note that step 4 is the last thing you do, but note that in your partial proof you have been opening up a whole bunch of subproofs without indicating how you intend to use them. That's a really bad habit, and it's exactly what gets you stuck!  Here's a post where I describe the 'correct' thought process for doing a specific Fitch proof.
