Try to stay away from areas where you know you will get negative comments, especially where there are non mahram men etc, and also stick with quite a few people in groups so you've always got backup and support.
I think you should leave it upto brothers to give dawah to guys, and you as sisters should give dawah to the females though, but if you feel they will be a major threat - then ignore them and move on.
Also remember these verses from Qur'an in your dawah:
Who is better in speech than one who calls (men) to Allah, works righteousness, and says, "I am of those who bow in Islam"?
Tafsir Qur'an Fussilat 41:34
[وَلاَ تَسْتَوِى الْحَسَنَةُ وَلاَ السَّيِّئَةُ]
(The good deed and the evil deed cannot be equal.) means, there is a huge difference between them.
[ادْفَعْ بِالَّتِى هِىَ أَحْسَنُ]
(Repel (the evil) with one which is better,) means, `when someone does you wrong, repel him by treating him well,' as `Umar, may Allah be pleased with him, said, "There is no better punishment for one who has disobeyed Allah with regard to you, than your obeying Allah with regard to him.''
[فَإِذَا الَّذِى بَيْنَكَ وَبَيْنَهُ عَدَاوَةٌ كَأَنَّهُ وَلِىٌّ حَمِيمٌ]
(then verily he, between whom and you there was enmity, (will become) as though he was a close friend.) means, `if you treat well those who treat you badly, this good deed will lead to reconciliation, love and empathy, and it will be as if he is a close friend to you and he will feel pity for you and be kind to you.' Then Allah says:
[وَمَا يُلَقَّاهَا إِلاَّ الَّذِينَ صَبَرُواْ]
(But none is granted it except those who are patient) meaning, no one accepts this advice and works according to it, except for those who can be patient in doing so, for it is difficult for people to do.
[وَمَا يُلَقَّاهَآ إِلاَّ ذُو حَظِّ عَظِيمٍ]
(and none is granted it except the owner of the great portion) means, the one who has a great portion of happiness in this world and in the Hereafter. `Ali bin Abi Talhah reported that Ibn `Abbas explained this Ayah: "Allah commands the believers to be patient when they feel angry, to be forbearing when confronted with ignorance, and to forgive when they are mistreated. If they do this, Allah will save them from the Shaytan and subdue their enemies to them until they become like close friends.''
[وَإِمَّا يَنَزَغَنَّكَ مِنَ الشَّيْطَـنِ نَزْغٌ فَاسْتَعِذْ بِاللَّهِ]
(And if an evil whisper from Shaytan tries to turn you away, then seek refuge in Allah.) means, the devils among men may be deceived by your kind treatment of him, but the devils among the Jinn, when they insinuate their evil whispers, cannot be dealt with except by seeking refuge with the Creator Who gave him power over you. If you seek refuge with Allah and turn to Him, He will stop him from harming you and bring his efforts to naught. When the Messenger of Allah stood up to pray, he would say:
«أَعُوذُ بِاللهِ السَّمِيعِ الْعَلِيمِ مِنَ الشَّيْطَانِ الرَّجِيمِ، مِنْ هَمْزِهِ وَنَفْخِهِ وَنَفْثِه»
(I seek refuge in Allah the All-Hearing, All-Knowing, from the accursed Shaytan and his evil insinuations, breath and impurity.)'' We have already stated that there is nothing like this in the Qur'an, apart from the passage in Surat Al-A`raf, where Allah says:
[خُذِ الْعَفْوَ وَأْمُرْ بِالْعُرْفِ وَأَعْرِض عَنِ الْجَـهِلِينَ - وَإِمَّا يَنَزَغَنَّكَ مِنَ الشَّيْطَـنِ نَزْغٌ فَاسْتَعِذْ بِاللَّهِ إِنَّهُ سَمِيعٌ عَلِيمٌ ]
(Show forgiveness, enjoin what is good, and turn away from the foolish. And if an evil whisper comes to you from Shaytan, then seek refuge with Allah. Verily, He is All-Hearer, All-Knower.) (7:199-200) and the passage in Surat Al-Mu'minun where Allah says:
[ادْفَعْ بِالَّتِى هِىَ أَحْسَنُ السَّيِّئَةَ نَحْنُ أَعْلَمُ بِمَا يَصِفُونَ - وَقُلْ رَّبِّ أَعُوذُ بِكَ مِنْ هَمَزَاتِ الشَّيـطِينِ - وَأَعُوذُ بِكَ رَبِّ أَن يَحْضُرُونِ ]
(Repel evil with that which is better. We are Best-Acquainted with the things they utter. And say: "My Lord! I seek refuge with You from the whisperings of the Shayatin. And I seek refuge with You, My Lord! lest they should come near me.'') (23:96-98)