Subject avoiding transaction exceptions

I am having no luck in avoiding Transaction Exceptions.
Initially I used the standard parameters for a transaction of


Then I got a lot of lock conflict on NO WAIT transaction exceptions.
SO I went to a lot of effort to change parameters of Transactions to:


No I get a lot of 

"deadlock update conflicts with concurrent update concurrent transaction"

So now I am stumped. All I want firebird to do is to wait for the previous transaction to finalise before it attempts to update a record. However I cannot seem to tell it to do that.

What to do?

Kind Regards,