I will add a translation next to the each phrase, so you can see what is only natural to ask if you have a friend who is from Serbia, Bosnia, Montenegro or Croatia :) You will see that there are no "safe" topics about the weather though, lol:)
Đesi ba?* = Where are you? =what's up?
šta ima? = what's up?
kako si? = how are you?
šta radiš? = what are you doing?
ima li šta novo da me iznenadiš?
= is there anything new to surprise me?
Kad si doš'o? = When did you come back?
kad se vraćaš? = when are you coming back?
vidiš li ti ovo? = can you see what's happening?
i kako ti to shvaćaš? = and what's your take on that?
Šta planiraš danas? = What are your plans for today? (what are you gonna do?)
jesi l' sutra šta planiro? = have you planned anything for tomorrow?
što si neraspoložen? = why are you in a bad mood?
ko te iznerviro? = who bothered you?
Jes' ti diplomiro ono što si studir'o? = finished what you've been studying?
Nešto s' ti to čini mi se malo pauziro? = it seems you didn't finish it in time?
Jes' to novi telefon kupio? = Have you bought a new (cell) phone?
pošto? = how much?
ako bi ga prodavo koliko bi košto? = if you were to sell it, how much would it be?
Kol'ko mu prostora u memoriju staje? = how much memory (space=prostor) is there?
kol'ko mu dugo baterija traje? = how long does the battery last?
Jesu l' to tvoja kola? = is this your car? (The word "kola" in Serbian is always in plural)
il je rent a car? = or is it a rent-a-car?
Je l' to dizel il' benzinac? = is it using diesel fuel or gasoline?
kol'ko je star? = how old is it?
Je l' to na lizing? =Is it on lease?
il je gotovina? = or in cash?
je l' to vuče prednja ili zadnja osovina? = is it front or rear traction?
Refren 2x (* kaš = Kad ćeš)
Kaš* se žent? = When are you gonna get married (ženiti = to get married for men)?
kaš se udavat? when are you gonna get married (udavati = to get married for women)?
De mi reci pa da mogu mirno spavat! = do tell me, so I can sleep peacefully!
imaš li djece? = have any kids?
e nemaš pa što? = no? so why not?
šta čekaš više? = what are you waiting for?
što ne rješavaš to? = why aren't you working on that?
Kako ti je mama? = How's your ma?
kako ti je tata? = how's your pa?
je l' ti ono imaš sestru ili brata? = have you got a sister or brother?
(The word "ono"implies that he has forgotten about it)
Radiš li šta? = working?
i kol'ka ti je plata? = how much is your salary?
jesi l' u kreditu? = having a (bank) loan?
kol'ka ti je rata? = how much is your (monthly) installment?
Đe budeš? = Where are you staying?
đe živiš?= where do you live?
đe stanuješ sada? =where are you living now?
je l' to periferija? = is it in the suburbs?
za kolko si do grada? = how far is it from the city center?
jesi to na fejsu? = are you on Facebook?
koja ti je slika na profilu? = which is your profile photo?
je l' de da to i ti imaš viška koju kilu? = do admit it that you have put on weight!
(some (extra) kilos = koju kilu viška)
*Đes ba or Gde si? here means "what's up", and is often used along with that phrase "Đes ba? Šta ima?