Class deeds have a maximum number of times they can be increased per day. 30/150 sounds like a typical daily increase total to me.
Check the progress bar in your deed log. If it is yellow, you have already reached your daily limit for this deed and need to wait until tomorrow until you can work on it again (or buy a skill deed accelerator in the Store, if you are really impatient about this deed).
If the progress bar is still blue, your deed should progress when you use the associated skill(s). In that case, maybe somebody who knows a bit more about the Burglar class than me can make a guess?
German, female, migrated from CodeMasters in 2011, Premium member, slow-leveller, pure PvEer and opposed to Forced Emotes - wherever I fit into the statistic, it's not in its middle.