Hi Pawel,
In today's competitive, sellers market, you really have to put your best offer or very very close to it up front. Have as clean an offer as possible ie: minimal or less subjects, decrease the closing time, or increase your earnest money (deposit). Have financing already in place so your offer is a "Cash offer." Put yourself in the shoes of the seller. If they have an all cash offer, little or no subjects, fast close vs one w/several subjects, minimal deposit, long wait time, it's a no brainer for them. Make it easy for them to get their house sold. You could also write them a cover letter introducing yourself & your intent for the property. Include a picture of you and your family or pet. If the sellers can somehow empathize with you, they may choose your offer over another perhaps better offer. It certainly doesn't hurt.
Keep making offers & eventually you'll land one, just be careful not to compromise your criteria. I usually just have the inspection subject to give myself at least 1 out. However, if I know I'm doing a full gut and I'm confident in all my #'s, I'll offer with no subjects.