Eco-labels
It is worth choosing goods with environmental certificates. The Ecolabel, also known as the daisy, has the widest geographical reach within the European Union. It has existed since 1992 and is awarded to products meeting high environmental standards. The oldest eco certificate is the Blue Angel (Blaue Engel), created in Germany in 1978. Qualifying products are assessed on the following factors: raw material efficiency, pollution reduction, noise reduction, waste elimination or reduction and potential for reuse. The register of ecological certificates can be found, for example, here: [http://www.ecolabelindex.com/ecolabels/]. In addition to ecological certificates, it is worth paying attention to social certificates, i.e. Fairtrade, Fair for Life, Fair Trade Certified, Fair Trade by Ecocert or products delivered by certified Fair Trade Organisations (members of the World Fair Trade Organization).

Green Public Procurement
On the website of the Public Procurement Office you will find environmental criteria for so-called green public procurement (GPP).  
This process focuses on minimising the environmental impact of goods and services throughout their life cycle. This means that price of a given product is not the sole criterion but the costs of energy, maintenance and final disposal should also be considered. For example, purchasing products with high energy or water efficiency can significantly reduce your utility bills. For instance, a green tender for printing services could include the following environmental criteria:
printing on recycled paper, with eco-friendly ink, using water-based glue;
description of production processes reducing environmental footprint (e,g, optimising printing sheets, use of ink, energy efficient machines, LED lighting);
packaging for shipment in accordance with zero/less waste approach: limiting plastics, using fillers for protection from paper cuttings or compostable materials (e.g. foam peanuts), using multiple-use packaging or recycled packaging;
offering ecological alternatives (selection of paper, ink, circulation, format) fit for a particular specification and not compromising on quality of print and aesthetics of the publication
Such criteria were used by the Zachęta National Art Gallery in Warsaw when ordering printing services.

In addition, there are a number of documents and certificates confirming pro-ecological approaches of companies to the environment, e.g. a report in the national database on the emissions of greenhouse gases and other substances – KOBIZE or an entry in the database on products and packaging and waste management (BDO). 
Green public procurement principles should be used while selecting any service or goods. Whether it is a tender for a cleaning company which uses environmentally friendly detergents, gardening services based on non-invasive gardening methods, or energy efficient computer/multimedia equipment.

Socially sustainable public procurement
As well as environmental indicators, which can be used in decision-making concerning potential cooperation, pay attention to the social policies of particular organisations. Do they promote decent work standards regardless of gender, age, disability, personal views, nationality, ethnicity, sexual orientation, while respecting human and labour rights? It is also worth promoting organisations operating in the field of the social and solidarity economy, micro-enterprises and small and medium-sized enterprises (SMEs) are also worth promoting. Does the company take into account the issues of fair and ethical trade, which can be confirmed by fair trade certificates? 
The website of the Public Procurement Office contains information on social criteria that can be used in a socially sustainable public procurement process.