Dear Kristina,
Thank you for sharing your experience.
You should definitely take more practice tests than just 2...Please be aware that the single best way to practice for the GMAT is to do as many practice tests as possible AFTER you have studied the verbal and quant. concepts!
It is crucial that you first of all get a foundation and total understanding of the underlying concepts. Then you should practice as many real GMAT question types and observe your progress. The areas where you still have weaknesses should get special attention and you should study them more intensively.
A private tutor can help you to identify your weaknesses and create a study plan to eliminate them. Although this is a relatively cost intensive way to prepare it is (and all would agree I think) the most efficient.
If you are interested in online private tutoring we can arrange a free and non-committal trial hour where you can meet your tutor and discuss further details with him. Alternatively, we can offer you a free 7 days trial account for our 180+ hours on demand course. In case you are interested please learn more about it under the following link:
https://www.optimus-prep.com/gmat-on-demand-coursePlease contact our support if you have any questions and please never forget that if you correctly prepare for the GMAT, your score is the direct result of the effort you put in!